US20200406202A1 - Ceramic support, zeolite membrane complex, method of producing zeolite membrane complex, and separation method - Google Patents
Ceramic support, zeolite membrane complex, method of producing zeolite membrane complex, and separation method Download PDFInfo
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- US20200406202A1 US20200406202A1 US17/015,413 US202017015413A US2020406202A1 US 20200406202 A1 US20200406202 A1 US 20200406202A1 US 202017015413 A US202017015413 A US 202017015413A US 2020406202 A1 US2020406202 A1 US 2020406202A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/108—Inorganic support material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/028—Molecular sieves
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0051—Inorganic membrane manufacture by controlled crystallisation, e,.g. hydrothermal growth
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/105—Support pretreatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/1213—Laminated layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/1216—Three or more layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/1218—Layers having the same chemical composition, but different properties, e.g. pore size, molecular weight or porosity
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/122—Separate manufacturing of ultra-thin membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
- B01D69/145—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing embedded catalysts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/024—Oxides
- B01D71/027—Silicium oxide
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/028—Molecular sieves
- B01D71/0281—Zeolites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
- C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
- C01B39/46—Other types characterised by their X-ray diffraction pattern and their defined composition
- C01B39/48—Other types characterised by their X-ray diffraction pattern and their defined composition using at least one organic template directing agent
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
- B01D2325/0233—Asymmetric membranes with clearly distinguishable layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/10—Catalysts being present on the surface of the membrane or in the pores
Definitions
- the present invention relates to a ceramic support, a zeolite membrane complex, a method of producing a zeolite membrane complex, a separation method of mixture of substances using a zeolite membrane complex.
- a method of immersing a porous ceramic support formed of aluminum oxide or the like in a starting material solution and synthesizing a zeolite membrane on the support by hydrothermal synthesis is known as one of methods of producing zeolite membrane complexes. Since the hydrothermal synthesis is performed under high temperature and pressure, there is a possibility that constituent components in the support may be eluted into the starting material solution. The substances eluted from the support may have an adverse effect on synthesis of zeolite membrane. Specifically, a zeolite membrane having a composition ratio different from a desired composition ratio may be synthesized. Performance of zeolite membrane may be degraded because of different phase synthesized as by-product in the zeolite membrane. Alternatively, defective coating on the support surface (e.g., pinholes in the zeolite membrane or the like) may be caused since the formation of the zeolite membrane is inhibited.
- defective coating on the support surface e.g., pinholes in the zeolite
- Japanese Patent No. 3316173 proposes a technique for reducing an elution amount of a support into a starting material solution by forming the support with tantalum oxide or niobium oxide.
- Japanese Patent No. 4961322 (Document 2) proposes an alumina substrate which is used as a support for zeolite membrane and which contains 1% to 4% by weight of alkali metal oxide and/or alkaline earth metal oxide.
- the support of Document 1 is formed of expensive material that is tantalum oxide or niobium oxide, and thus, production cost of the zeolite membrane complex increases. Since the support of Document 2 contains a relatively large amount of alkali metal or alkaline earth metal, there may be a case where abnormality (for example, difference in a composition ratio of the zeolite membrane, performance degradation due to different phase synthesized as by-product, or defect such as pinholes) occurs in the zeolite membrane by elution of alkali metal or alkaline earth metal from the support during hydrothermal synthesis.
- abnormality for example, difference in a composition ratio of the zeolite membrane, performance degradation due to different phase synthesized as by-product, or defect such as pinholes
- the present invention is intended for a porous ceramic support for supporting a zeolite membrane.
- a hydraulic conductivity is less than or equal to 1.1 ⁇ 10 ⁇ 3 m/s, and a total content of alkali metal and alkaline earth metal in a surface part within 30 ⁇ m from a surface in a depth direction perpendicular to the surface is less than or equal to 1% by weight.
- a porosity of the surface part is less than or equal to 50%.
- the support includes an intermediate layer including the surface part, and a support layer that supports the intermediate layer from a side opposite to a surface of the intermediate layer which comes into contact with a zeolite membrane, the support layer having a mean particle diameter greater than that of the intermediate layer.
- the present invention is also intended for a zeolite membrane complex.
- the zeolite membrane complex according to a preferable embodiment of the present invention includes the above ceramic support, and a zeolite membrane formed on the ceramic support.
- a percentage of surface abnormality in a surface of the zeolite membrane is less than or equal to 15%.
- a thickness of the zeolite membrane is greater than or equal to 0.1 ⁇ m and less than or equal to 30 ⁇ m.
- a content of silicon oxide in the zeolite membrane is 10 times or more a content of aluminum oxide.
- the present invention is also intended for a method of producing a zeolite membrane complex.
- the method of producing a zeolite membrane complex according to a preferable embodiment of the present invention includes a) preparing the above ceramic support, b) preparing seed crystals, c) depositing the seed crystals on the ceramic support, and d) immersing the ceramic support in a starting material solution and growing zeolite from the seed crystals by hydrothermal synthesis, to thereby form a zeolite membrane on the ceramic support.
- the present invention is also intended for a separation method.
- the separation method according to a preferable embodiment of the present invention includes a) preparing the above zeolite membrane complex, and b) supplying a mixture of substances containing a plurality of types of gases or liquids to the zeolite membrane complex and allowing a high-permeability substance in the mixture of substances to permeate through the zeolite membrane complex, to thereby separate the high-permeability substance from other substances.
- the mixture of substances includes at least one of following substances: hydrogen, helium, nitrogen, oxygen, water, steam, carbon monoxide, carbon dioxide, nitrogen oxide, ammonia, sulfur oxide, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- substances hydrogen, helium, nitrogen, oxygen, water, steam, carbon monoxide, carbon dioxide, nitrogen oxide, ammonia, sulfur oxide, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- FIG. 1 is a sectional view of a zeolite membrane complex
- FIG. 2 is an enlarged sectional view of the zeolite membrane complex
- FIG. 3 is a flowchart of production of the zeolite membrane complex
- FIG. 4 is a view of a separation apparatus
- FIG. 5 is a flowchart of separation of a mixture of substances
- FIG. 6 is an X-ray diffraction pattern of a zeolite membrane according to an example
- FIG. 7 is an X-ray diffraction pattern of a zeolite membrane according to a comparative example
- FIG. 8 is a view showing a relationship between hydrothermal synthesis time and nitrogen permeation amount
- FIG. 9 is a view of a surface of the zeolite membrane according to the example.
- FIG. 10 is a view of a surface of the zeolite membrane according to the comparative example.
- FIG. 11 is a view of a surface of a zeolite membrane according to an example
- FIG. 12 is a view of a surface of a zeolite membrane according to an example.
- FIG. 13 is a view of a surface of a zeolite membrane according to a comparative example.
- FIG. 1 is a sectional view of a zeolite membrane complex 1 according to an embodiment of the present invention.
- the zeolite membrane complex 1 includes a porous ceramic support 11 and a zeolite membrane 12 formed on a surface of the ceramic support 11 .
- the ceramic support 11 is a support for supporting a zeolite membrane, and hereinafter is simply referred to as “support 11 ”.
- the support 11 is a monolith support, having a substantially circular columnar shape, where a plurality of through holes 111 each extending in a longitudinal direction (i.e., the vertical direction in the drawing) are formed.
- Each through hole 111 i.e., cell
- Each through hole 111 has, for example, a substantially circular cross-section perpendicular to the longitudinal direction.
- the diameter of the through holes 111 is greater than the actual diameter, and the number of through holes 111 is smaller than the actual number.
- the zeolite membrane 12 is formed on the inner surfaces of the through holes 111 and covers substantially the entire inner surfaces of the through holes 111 . In FIG. 1 , the zeolite membrane 12 is illustrated with bold lines.
- the support 11 has a length (i.e., the length in the vertical direction in the drawing) of, for example, 10 cm to 200 cm.
- the support 11 has an outer diameter of, for example, 0.5 cm to 30 cm.
- the distance between the central axes of each pair of adjacent through holes 111 is, for example, in the range of 0.3 mm to 10 mm.
- the surface roughness (Ra) of the support 11 is, for example, in the range of 0.1 ⁇ m to 2.0 ⁇ m and preferably in the range of 0.2 ⁇ m to 1.0 ⁇ m.
- the support 11 may have a different shape such as a honeycomb shape, a flat plate shape, a tubular shape, a circular cylindrical shape, a circular columnar shape, or a polygonal prism shape.
- a honeycomb shape a flat plate shape
- a tubular shape a circular cylindrical shape
- a circular columnar shape a circular columnar shape
- a polygonal prism shape When having a tubular shape, the support 11 has a thickness of, for example, 0.1 mm to 10 mm.
- the support 11 is a porous member permeable to gases and liquids (i.e., fluids).
- the zeolite membrane 12 is a molecular separation membrane that separates a specific substance from a mixed fluid obtained by mixing a plurality of types of substances, using a molecular sieving function.
- the zeolite membrane 12 may be used as a gas separation membrane that separates a specific gas from a mixed gas containing a plurality of types of gases.
- the zeolite membrane 12 may be used as a liquid separation membrane that separates a specific liquid from a mixed liquid containing a plurality of types of liquids.
- the zeolite membrane 12 may be used as a separation membrane that separates a specific substance from a mixed fluid obtained by mixing a gas(es) and a liquid(s).
- the zeolite membrane 12 may be used as a pervaporation membrane.
- the zeolite membrane complex 1 may be used for other applications.
- the material for the support 11 various ceramics may be employed as long as they have chemical stability in the step of forming the zeolite membrane 12 on the surface.
- the ceramic sintered compact to be selected as the material for the support 11 include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide.
- the support 11 contains at least one of alumina, silica, and mullite.
- the support 11 may contain an inorganic binder.
- the inorganic binder may be at least one of titania, mullite, easily sinterable alumina, silica, glass frit, clay minerals, and easily sinterable cordierite.
- the support 11 contains alkali metal and/or alkaline earth metal.
- the alkali metal and alkaline earth metal are, for example, sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), or the like.
- the support 11 has a hydraulic conductivity less than or equal to 1.1 ⁇ 10 ⁇ 3 m/s, preferably less than or equal to 5.8 ⁇ 10 ⁇ 4 m/s, and more preferably less than or equal to 2.3 ⁇ 10 ⁇ 4 m/s.
- the lower limit of the hydraulic conductivity of the support 11 is not particularly limited as long as it is greater than 0 m/s.
- the hydraulic conductivity is typically greater than or equal to 1.1 ⁇ 10 ⁇ 5 m/s, and more typically greater than or equal to 1.2 ⁇ 10 ⁇ 4 m/s.
- the hydraulic conductivity of the support 11 was measured as below. First, by sealing one end of the support 11 in the longitudinal direction, one side of each through hole 111 (i.e., cell) of the support 11 was blocked. Subsequently, distilled water was supplied into the through holes 111 from the other end of the support 11 in the longitudinal direction. At this time, the flow rate, pressure, and temperature of the supplied distilled water were measured. Next, the flow rate of distilled water that is led out from the outer side face of the support 11 through the support 11 was measured.
- the measured results were converted into values under a pressurized condition of 0.1 MPa at a water temperature of 25° C., and the hydraulic conductivity that is an amount of water per unit area which permeates through the support 11 per unit time was obtained on the basis of the converted values.
- FIG. 2 is a sectional view of part of the zeolite membrane complex 1 in enlarged dimensions.
- the support 11 is a layered structure including an intermediate layer 112 and a support layer 113 .
- the material for each of the intermediate layer 112 and the support layer 113 may be any of the above-described materials.
- the intermediate layer 112 and the support layer 113 may be formed of the same material, or may be formed of different materials.
- the intermediate layer 112 is in direct contact with the zeolite membrane 12 to support the zeolite membrane 12 .
- the surface 114 of the intermediate layer 112 which is in contact with the zeolite membrane 12 is the inner surfaces of the through holes 111 of the support 11 .
- the support layer 113 supports the intermediate layer 112 from a side opposite to the zeolite membrane 12 .
- the support layer 113 supports the intermediate layer 112 from the side opposite to the surface 114 of the intermediate layer 112 which is in contact with the zeolite membrane 12 .
- FIG. 2 a portion of the support 11 in the vicinity of the intermediate layer 112 is illustrated.
- the intermediate layer 112 is formed of particles having a relatively small mean particle diameter.
- the support layer 113 is formed of particles having a mean particle diameter greater than that of the intermediate layer 112 .
- the mean particle diameter of the particles constituting the intermediate layer 112 is preferably in the range of 0.001 ⁇ m to 100 ⁇ m, more preferably in the range of 0.01 ⁇ m to 80 ⁇ m, and yet more preferably in the range of 0.1 ⁇ m to 50 ⁇ m.
- the mean particle diameter of the particles constituting the support layer 113 is preferably in the range of 5 ⁇ m to 200 ⁇ m, more preferably in the range of 25 ⁇ m to 170 ⁇ m, and yet more preferably in the range of 50 ⁇ m to 150 ⁇ m.
- a polished surface formed by polishing the intermediate layer 112 is observed with a scanning electron microscope (SEM), and an average of particle diameters of twenty framework particles which are randomly selected is obtained as the mean particle diameter of the intermediate layer 112 .
- the particle diameter of each framework particle is obtained as an average of the maximum diameter and the minimum diameter of the framework particle. The same applies to the mean particle diameter of the support layer 113 .
- the mean pore diameter of the intermediate layer 112 is less than the mean pore diameter of the support layer 113 .
- the mean pore diameter of the intermediate layer 112 is preferably in the range of 0.001 ⁇ m to 1 ⁇ m, more preferably in the range of 0.01 ⁇ m to 1 ⁇ m, and yet more preferably in the range of 0.05 ⁇ m to 0.5 ⁇ m.
- the mean pore diameter of the support layer 113 is preferably in the range of 0.5 ⁇ m to 50 ⁇ m, more preferably in the range of 1 ⁇ m to 30 ⁇ m, and yet more preferably in the range of 10 ⁇ m to 25 ⁇ m.
- the mean pore diameters of the intermediate layer 112 and the support layer 113 can be measured by, for example, a mercury porosimeter, a perm porosimeter, or a nano-perm porosimeter.
- the porosity of the intermediate layer 112 is preferably less than or equal to 50%, more preferably less than or equal to 40%, and yet more preferably less than or equal to 30%.
- the lower limit of the porosity of the intermediate layer 112 is not particularly limited as long as it is greater than 0%.
- the porosity is typically greater than or equal to 5%, and more typically greater than or equal to 10%.
- the porosity of the support layer 113 is preferably in the range of 5% to 50%, more preferably in the range of 10% to 45%, and yet more preferably in the range of 15% to 40%.
- the porosity of the support layer 113 was measured by mercury injection with only the support layer 113 as the measurement target.
- the porosity of the intermediate layer 112 was obtained by acquiring an image of the section of the intermediate layer 112 with an electron microscope and by performing an image analysis on an image obtained by binarizing the acquired image.
- the thickness of the intermediate layer 112 is, for example, in the range of 5 ⁇ m to 500 ⁇ m, preferably in the range of 10 ⁇ m to 400 ⁇ m, and more preferably in the range of 15 ⁇ m to 300 ⁇ m.
- the thickness of the intermediate layer 112 is a distance between the surface 114 of the intermediate layer 112 and the surface 115 of the support layer 113 in a depth direction substantially perpendicular to the surface 114 of the intermediate layer 112 (i.e., the radial direction of the through hole 111 of the support 11 ).
- the positions of the surface 114 of the intermediate layer 112 and the surface 115 of the support layer 113 can be obtained, for example, by observing the SEM image of the section of the support 11 .
- a portion of the support 11 within 30 ⁇ m from the surface 114 in the above depth direction is referred to as a “surface part 116 ”.
- the surface part 116 refers to, in the support 11 , the whole of the portion between a position at 30 ⁇ m depth from the surface 114 and the surface 114 of the support 11 .
- the thickness of the intermediate layer 112 is greater than 30 ⁇ m, the whole of the surface part 116 is included in the intermediate layer 112 and part of the intermediate layer 112 exists between the surface part 116 and the support layer 113 , as shown in FIG. 2 .
- the thickness of the intermediate layer 112 is 30 ⁇ m, the surface part 116 is identical to the intermediate layer 112 . In any of these cases, the intermediate layer 112 includes the whole of the surface part 116 .
- the porosity of the surface part 116 is the same as that of the intermediate layer 112 . Specifically, the porosity of the surface part 116 is preferably less than or equal to 50%, more preferably less than or equal to 40%, and yet more preferably less than or equal to 30%. The lower limit of the porosity of the surface part 116 is not particularly limited as long as it is greater than 0%. The porosity is typically greater than or equal to 5%, and more typically greater than or equal to 10%.
- the mean particle diameter of the framework particles and the mean pore diameter in the surface part 116 are the same as those of the intermediate layer 112 .
- the support 11 contains at least one of alkali metal and alkaline earth metal, the support 11 may not contain both of them as appropriate. In this regard, when the support 11 does not contain both of alkali metal and alkaline earth metal, the sintering temperature of the support 11 tends to increase.
- the total content of alkali metal and alkaline earth metal in the surface part 116 is less than or equal to 1% by weight, preferably less than or equal to 0.5% by weight, more preferably less than or equal to 0.1% by weight.
- the lower limit of the total content is not particularly limited.
- the total content is typically greater than or equal to 0.0001% by weight, and more typically greater than or equal to 0.001% by weight.
- the total content of alkali metal and alkaline earth metal can be measured by X-ray photoelectron spectrometry.
- the intermediate layer 112 is produced, for example, as below. First, an aggregate for the intermediate layer 112 , an organic binder, a pH adjuster, and a surfactant are added to water, and they are mixed for 12 hours or more with a ball mill.
- the purpose of mixing is not pulverization of the intermediate layer aggregate but peptization (loosening), and thus, balls having a lower hardness than the intermediate layer aggregate are used in the ball mill.
- the intermediate layer aggregate is made of alumina, zirconia balls are used in the ball mill.
- the slurry concentration (i.e., concentration of the intermediate layer aggregate) in ball milling is preferably less than or equal to 50%. Since the slurry concentration is made less than or equal to 50%, it is conceivable that the organic binder, the pH adjuster, and the surfactant become easy to act on the intermediate layer aggregate. After that, the above slurry is diluted with a predetermined amount of water. A defoamer is preferably added to the water.
- a pH adjuster is added to the water to substantially equalize the pH of the water containing the defoamer and the pH adjuster with the pH of the slurry before dilution with the water. Therefore, occurrence of re-flocculation due to change in pH of the slurry by the defoamer can be suppressed.
- the slurry diluted with the water is degassed with stirring under vacuum, and therefore the slurry for the intermediate layer 112 is prepared. Since the dispersibility of the slurry for the intermediate layer 112 is improved by the above step, it is possible to obtain the intermediate layer 112 having high strength with reduced total content of alkali metal and alkaline earth metal even when the firing temperature is relatively low.
- An inorganic binder e.g., titanium oxide or the like
- the thickness of the zeolite membrane 12 is, for example, in the range of 0.1 ⁇ m to 30 ⁇ m, preferably in the range of 0.5 ⁇ m to 20 ⁇ m, and more preferably in the range of 1 ⁇ m to 10 ⁇ m. As the thickness of the zeolite membrane 12 increases, separation performance improves. As the thickness of the zeolite membrane 12 decreases, permeance increases.
- the surface roughness (Ra) of the zeolite membrane 12 is, for example, 5 ⁇ m or less, preferably 2 ⁇ m or less.
- the type of the zeolite constituting the zeolite membrane 12 is not particularly limited.
- the maximum number of membered rings in the zeolite is preferably 6 or 8 from the view point of permeation amount of permeable substances and separation performance. More preferably, the maximum number of membered rings in the zeolite membrane 12 is 8.
- the zeolite membrane 12 is made of, for example, AFX-type zeolite.
- the zeolite membrane 12 is made of a zeolite having a framework type code “AFX” assigned by the International Zeolite Association.
- the intrinsic pore diameter of the zeolite constituting the zeolite membrane 12 is 0.34 nm ⁇ 0.36 nm.
- the intrinsic pore diameter of the zeolite membrane 12 is smaller than the mean pore diameter of the support 11 .
- the zeolite membrane 12 is not limited to the AFX-type zeolite, but may also be zeolite having any one of other structures.
- the zeolite membrane 12 may be any type of zeolite, for example, AEI-type, AEN-type, AFN-type, AFV-type, CHA-type, DDR-type, ERI-type, ETL-type, GIS-type, LEV-type, LTA-type, RHO-type, and SAT-type.
- the zeolite membrane 12 contains, for example, one or more of the followings: silicon (Si), aluminum (Al), and phosphorus (P).
- the zeolite membrane 12 is made of aluminosilicate zeolite containing at least Al, Si, and O (oxygen).
- the zeolite membrane 12 contains aluminum oxide (Al 2 O 3 ) and silicon dioxide (SiO 2 ).
- the content of SiO 2 is preferably 10 times or more the content of Al 2 O 3 .
- the silica/alumina ratio in the zeolite membrane 12 is preferably greater than or equal to 10.
- the silica/alumina ratio is more preferably greater than or equal to 12, and yet more preferably greater than or equal to 20.
- the upper limit of the silica/alumina ratio in the zeolite membrane 12 is not particularly limited.
- the silica/alumina ratio is typically less than or equal to 10000, and more typically less than or equal to 1000.
- a support 11 for use in the production of the zeolite membrane complex 1 is prepared (step S 11 ).
- seed crystals for use in the production of the zeolite membrane 12 are prepared (step S 12 ).
- AFX-type zeolite powder is synthesized by hydrothermal synthesis, and the seed crystals are acquired from the zeolite powder.
- This zeolite powder may be used as-is as seed crystals, or may be processed into seed crystals by, for example, pulverization.
- Step S 11 and step S 12 may be performed in parallel, or step S 12 may be performed before step S 11 .
- the porous support 11 is immersed in a solution in which the seed crystals are dispersed, so that the seed crystals are deposited on the support 11 (step S 13 ).
- a solution in which the seed crystals are dispersed may be brought into contact with a portion of the support 11 on which the zeolite membrane 12 is desired to be formed, so that the seed crystals are deposited on the support 11 .
- a seed-crystal-deposited support is prepared.
- the seed crystals may be deposited by other methods on the support 11 .
- the support 11 with the seed crystals deposited thereon is immersed in a starting material solution.
- the starting material solution is prepared by, for example, dissolving substances such as an Si source, Al source, and a structure-directing agent (hereinafter, also referred to as an “SDA”) in a solvent such as water.
- the starting material solution has, for example, a composition of 1Al 2 O 3 :23SiO 2 :10Na 2 O:2.8SDA:1000H 2 O.
- SDA contained in the starting material solution for example, 1,4-diazabicyclo[2.2.2]octane-C4-diquat dibromide can be used in the case of AFX-type zeolite.
- AFX-type zeolite is grown by hydrothermal synthesis using the seed crystals as nuclei to form an AFX-type zeolite membrane 12 on the support 11 (step S 14 ).
- the temperature of the hydrothermal synthesis is preferably in the range of 110 to 200° C. and, for example, 160° C.
- the hydrothermal synthesis time is preferably in the range of 10 to 100 hours and, for example, 30 hours.
- the composition of the AFX-type zeolite membrane 12 can be adjusted by adjusting, for example, the composition ratio of the Si source and the Al source in the starting material solution.
- the support 11 and the zeolite membrane 12 are rinsed with deionized water. After the rinsing, the support 11 and the zeolite membrane 12 are dried at, for example, 80° C. After the support 11 and the zeolite membrane 12 have been dried, the zeolite membrane 12 is subjected to heat treatment so as to burn and remove the SDA in the zeolite membrane 12 and to cause micropores in the zeolite membrane 12 to come through the membrane (step S 15 ).
- the heating temperature and heating time for the zeolite membrane 12 are, for example, 450° C. and 50 hours. In this way, the aforementioned zeolite membrane complex 1 is obtained. In the case where any SDA is not used for production of the zeolite membrane 12 , step S 15 of burning and removing the SDA is omitted.
- FIG. 4 is a view of a separation apparatus 2 .
- FIG. 5 is flowchart of the separation of the mixture of substances by the separation apparatus 2 .
- the separation apparatus 2 supplies a mixture of substances containing a plurality of types of fluids (i.e., gases or liquids) to the zeolite membrane complex 1 and allows a substance with high permeability in the mixture of substances to pass through the zeolite membrane complex 1 so as to separate the substance from other substances.
- the separation by the separation apparatus 2 may be performed for the purpose of, for example, extracting a substance with high permeability from the mixture of substances or for the purpose of condensing a substance with low permeability.
- the mixture of substances may be a mixed gas containing a plurality of types of gases, or may be a mixed liquid containing a plurality of types of liquids, or may be a gas-liquid two-phase fluid containing both gas and liquid.
- the CO 2 permeation amount (permeance) through the zeolite membrane complex 1 at a temperature of 20° C. to 400° C. is, for example, 100 nmol/m 2 ⁇ s ⁇ Pa or more.
- the ratio of CO 2 permeation amount to CH 4 leakage amount (permeance ratio) in the zeolite membrane complex 1 at a temperature of 20° C. to 400° C. is, for example, 100 or higher.
- the mixture of substances contains, for example, one or more types of substances including hydrogen (H 2 ), helium (He), nitrogen (N 2 ), oxygen (O 2 ), water (H 2 O), steam (H 2 O), carbon monoxide (CO), carbon dioxide (CO 2 ), nitrogen oxide, ammonia (NH 3 ), sulfur oxide, hydrogen sulfide (H 2 S), sulfur fluoride, mercury (Hg), arsine (AsH 3 ), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- substances including hydrogen (H 2 ), helium (He), nitrogen (N 2 ), oxygen (O 2 ), water (H 2 O), steam (H 2 O), carbon monoxide (CO), carbon dioxide (CO 2 ), nitrogen oxide, ammonia (NH 3 ), sulfur oxide, hydrogen sulfide (H 2 S), sulfur fluoride, mercury (
- Nitrogen oxide is a compound of nitrogen and oxygen.
- the aforementioned nitrogen oxide is, for example, a gas called NO x such as nitrogen monoxide (NO), nitrogen dioxide (NO 2 ), nitrous oxide (also referred to as dinitrogen monoxide) (N 2 O), dinitrogen trioxide (N 2 O 3 ), dinitrogen tetroxide (N 2 O 4 ), or dinitrogen pentoxide (N 2 O 5 ).
- NO x nitrogen monoxide
- NO 2 nitrogen dioxide
- nitrous oxide also referred to as dinitrogen monoxide
- N 2 O 3 dinitrogen trioxide
- N 2 O 4 dinitrogen tetroxide
- N 2 O 5 dinitrogen pentoxide
- Sulfur oxide is a compound of sulfur and oxygen.
- the aforementioned sulfur oxide is, for example, a gas called SO x such as sulfur dioxide (SO 2 ) or sulfur trioxide (SO 3 ).
- Sulfur fluoride is a compound of fluorine and sulfur.
- the aforementioned sulfur fluoride is, for example, disulfur difluoride (F—S—S—F, S ⁇ SF 2 ), sulfur difluoride (SF 2 ), sulfur tetrafluoride (SF 4 ), sulfur hexafluoride (SF 6 ), or disulfur decafluoride (S 2 F 10 ).
- C1 to C8 hydrocarbons are hydrocarbons containing one to eight carbon atoms.
- C3 to C8 hydrocarbons may be any one of a linear-chain compound, a side-chain compound, and a cyclic compound.
- C3 to C8 hydrocarbons may also be either a saturated hydrocarbon (i.e., the absence of double bond and triple bond in a molecule) or an unsaturated hydrocarbon (i.e., the presence of double bond and/or triple bond in a molecule).
- C1 to C4 hydrocarbons are, for example, methane (CH 4 ), ethane (C 2 H 6 ), ethylene (C 2 H 4 ), propane (C 3 H 8 ), propylene (C 3 H 6 ), normal butane (CH 3 (CH 2 ) 2 CH 3 ), isobutane (CH(CH 3 ) 3 ), 1-butene (CH 2 ⁇ CHCH 2 CH 3 ), 2-butene (CH 3 CH ⁇ CHCH 3 ), or isobutene (CH 2 ⁇ C(CH 3 ) 2 ).
- the aforementioned organic acid is, for example, carboxylic acid or sulfonic acid.
- the carboxylic acid is, for example, formic acid (CH 2 O 2 ), acetic acid (C 2 H 4 O 2 ), oxalic acid (C 2 H 2 O 4 ), acrylic acid (C 3 H 4 O 2 ), or benzoic acid (C 6 H 5 COOH).
- the sulfonic acid is, for example, ethane sulfonic acid (C 2 H 6 O 3 S).
- the organic acid may be a chain compound or a cyclic compound.
- the aforementioned alcohol is, for example, methanol (CH 3 OH), ethanol (C 2 H 5 OH), isopropanol (2-propanol) (CH 3 CH(OH)CH 3 ), ethylene glycol (CH 2 (OH)CH 2 (OH)), or butanol (C 4 H 9 OH).
- the mercaptans are organic compounds with hydrogenated sulfur (SH) at their terminals and are substances called also thiol or thioalcohol.
- the aforementioned mercaptans are, for example, methyl mercaptan (CH 3 SH), ethyl mercaptan (C 2 H 5 SH), or 1-propane thiol (C 3 H 7 SH).
- the aforementioned ester is, for example, formic acid ester or acetic acid ester.
- the aforementioned ether is, for example, dimethyl ether ((CH 3 ) 2 O), methyl ethyl ether (C 2 H 5 OCH 3 ), or diethyl ether ((C 2 H 5 ) 2 O).
- the aforementioned ketone is, for example, acetone ((CH 3 ) 2 CO), methyl ethyl ketone (C 2 H 5 COCH 3 ), or diethyl ketone ((C 2 H 5 ) 2 CO).
- aldehyde is, for example, acetaldehyde (CH 3 CHO), propionaldehyde (C 2 H 5 CHO), or butanal (butyraldehyde) (C 3 H 7 CHO).
- the following description takes the example of the case where the mixture of substances separated by the separation apparatus 2 is a mixed gas containing a plurality of types of gases.
- the separation apparatus 2 includes the zeolite membrane complex 1 , sealing parts 21 , an outer casing 22 , seal members 23 , a supply part 26 , a first collecting part 27 , and a second collecting part 28 .
- the zeolite membrane complex 1 , the sealing parts 21 , and the seal members 23 are housed in the outer casing 22 .
- the supply part 26 , the first collecting part 27 , and the second collecting part 28 are disposed outside the outer casing 22 and connected to the outer casing 22 .
- the sealing parts 21 are members mounted on the opposite ends of the support 11 of the zeolite membrane complex 1 in the longitudinal direction and for covering and sealing the opposite end faces of the support 11 in the longitudinal direction.
- the sealing parts 21 prevent the inflow and outflow of gases through the opposite end faces of the support 11 .
- the sealing parts 21 are, for example, plate-like members formed of glass. The material and shape of each sealing part 21 may be appropriately changed.
- the opposite ends of each through hole 111 of the support 11 in the longitudinal direction are not covered by the sealing parts 21 . This allows the inflow and outflow of the mixed gas from these opposite ends into the through holes 111 .
- the outer casing 22 is a tubular member of a substantially circular cylindrical shape.
- the longitudinal direction of the zeolite membrane complex 1 (the horizontal direction in the drawing) is substantially parallel to the longitudinal direction of the outer casing 22 .
- One end of the outer casing 22 in the longitudinal direction i.e., left-side end in the drawing
- has a supply port 221 and the other end thereof has a first exhaust port 222 .
- the side face of the outer casing 22 has a second exhaust port 223 .
- the internal space of the outer casing 22 is an enclosed space isolated from the space around the outer casing 22 .
- the supply port 221 is connected to the supply part 26 .
- the supply part 26 supplies a mixed gas to the internal space of the outer casing 22 through the supply port 221 .
- the supply part 26 is a blower that transmits the mixed gas under pressure toward the outer casing 22 .
- the blower includes a pressure regulator that regulates the pressure of the mixed gas supplied to the outer casing 22 .
- the first exhaust port 222 is connected to the first collecting part 27 .
- the second exhaust port 223 is connected to the second collecting part 28 .
- the first collecting part 27 and the second collecting part 28 are, for example, reservoirs for storing gases derived from the outer casing 22 .
- the seal members 23 are disposed around the entire circumference between the outer side face of the zeolite membrane complex 1 (i.e., the outer side face of the support 11 ) and the inner side face of the outer casing 22 in the vicinity of the opposite ends of the zeolite membrane complex 1 in the longitudinal direction.
- Each seal member 23 is a substantially circular ring-shaped member formed of a material impermeable to gases.
- the seal members 23 are 0 rings formed of a resin having flexibility.
- the seal members 23 are in intimate contact with the outer side face of the zeolite membrane complex 1 and the inner side face of the outer casing 22 around the entire circumference.
- the space between the seal member 23 and the outer side face of the zeolite membrane complex 1 and the space between the seal member 23 and the inner side face of the outer casing 22 are sealed so as to disable the passage of gases.
- the aforementioned separation apparatus 2 is provided to prepare the zeolite membrane complex 1 (step S 21 ). Then, the mixed gas containing a plurality of types of gases having different permeability to the zeolite membrane 12 is supplied from the supply part 26 to the internal space of the outer casing 22 .
- the mixed gas is composed primarily of CH 4 , CO 2 , and N 2 .
- the mixed gas may contain gases other than CH 4 , CO 2 , and N 2 .
- the pressure of the mixed gas supplied from the supply part 26 to the internal space of the outer casing 22 i.e., initial pressure
- the mixed gas supplied from the supply part 26 to the outer casing 22 is introduced from the left end of the zeolite membrane complex 1 in the drawing into each through hole 111 of the support 11 as indicated by an arrow 251 .
- Gases having high permeability e.g., CO 2 and N 2 ; hereinafter referred to as “high-permeability substances” in the mixed gas pass through the zeolite membrane 12 provided on the inner side face of each through hole 111 and the support 11 , and are emitted from the outer side face of the support 11 .
- high-permeability substances are separated from gases with low permeability (e.g., CH 4 ; hereinafter referred to as a “low-permeability substance”) in the mixed gas (step S 22 ).
- the gases emitted from the outer side face of the support 11 i.e., high-permeability substances
- impermeable substances gases other than the gases that have passed through the zeolite membrane 12 and the support 11 (hereinafter, referred to as “impermeable substances”) pass through each through hole 111 of the support 11 from the left side to the right side in the drawing and are collected by the first collecting part 27 through the first exhaust port 222 as indicated by an arrow 252 .
- the impermeable substances may contain high-permeability substances that did not pass through the zeolite membrane 12 .
- Examples 1 to 8 and Comparative Examples 1 to 4 each showing the relationship between properties of the support 11 and separation performance of the zeolite membrane 12 will be described with reference to Tables 1 and 2, and FIGS. 6 to 13 .
- the hydraulic conductivity in Table 1 is a hydraulic conductivity of the support 11 .
- the total content in Table 1 is a total content of alkali metal and alkaline earth metal in the surface part 116 .
- the porosity in Table 1 is a porosity of the surface part 116 .
- the hydraulic conductivity of the support 11 was less than or equal to 1.1 ⁇ 10 ⁇ 3 m/s, and the total content of alkali metal and alkaline earth metal in the surface part 116 was less than or equal to 1% by weight.
- the hydraulic conductivity of the support was greater than 1.1 ⁇ 10 ⁇ 3 m/s, and the total content of alkali metal and alkaline earth metal in the surface part was greater than 1% by weight.
- FIG. 6 is an X-ray diffraction pattern obtained by measuring the zeolite membrane 12 of Example 1 with an X-ray diffraction (XRD) apparatus.
- FIG. 7 is an X-ray diffraction pattern obtained by measuring the zeolite membrane of Comparative Example 1 with the X-ray diffraction apparatus.
- the X-ray diffraction pattern of the zeolite membrane is indicated by the solid line
- the X-ray diffraction pattern of AFX-type zeolite crystal is indicated by the dashed line.
- MiniFlex600 manufactured by Rigaku Corporation was used for the measurement of the X-ray diffraction pattern.
- the X-ray used for the X-ray diffraction is a CuK ⁇ line. Further, an output of the X-ray is 600 W.
- the tube voltage was 40 kV
- the tube current was 15 mA
- the scanning speed was 5°/min
- the scanning step was 0.02°.
- a scintillation counter was used as a detector.
- the divergence slit was 1.25°
- the scattering slit was 1.25°
- the receiving slit was 0.3 mm
- the incident solar slit was 5.0°
- the light-receiving solar slit was 5.0°.
- a monochromator was not used, and a nickel foil having a thickness of 0.015 mm was used as a CuK ⁇ line filter.
- the AFX-type zeolite membrane of Comparative Example 1 includes different phase having a different composition from that of the AFX-type zeolite while the zeolite membrane 12 of Example 1 is almost single-phase AFX-type zeolite.
- peaks (and halos) corresponding to the different phase appear at positions indicated by arrows 81 , 82 . It is conceivable that the different phase in Comparative Example 1 is formed because of elution of alkali metal and/or alkaline earth metal contained in the surface part of the support during hydrothermal synthesis.
- Example 2 to 8 and Comparative Examples 2 to 4 the presence or absence of different phase was determined by XRD in the same way as Example 1 and Comparative Example 1.
- the zeolite membrane 12 of each of Examples 2 to 5 was almost single-phase AFX-type zeolite and included almost no different phase, similar to Example 1.
- the AFX-type zeolite membrane of Comparative Example 2 included different phase having a different composition from that of the AFX-type zeolite, similar to Comparative Example 1.
- the zeolite membrane 12 of each of Examples 6 and 7 was almost single-phase DDR-type zeolite and included almost no different phase.
- the DDR-type zeolite membrane of Comparative Example 3 included different phase having a different composition from that of the DDR-type zeolite.
- the zeolite membrane 12 of Example 8 was almost single-phase CHA-type zeolite and included almost no different phase.
- the CHA-type zeolite membrane of Comparative Example 4 included different phase having a different composition from that of the CHA-type zeolite.
- FIG. 8 is a view showing a relationship between hydrothermal synthesis time in production of the zeolite membrane 12 of Example 1 and N 2 permeation amount (nmol/m 2 ⁇ s ⁇ Pa) in the zeolite membrane 12 synthesized by the hydrothermal synthesis.
- the relationship in the zeolite membrane of Comparative Example 1 is also shown.
- the zeolite membrane 12 of Example 1 became denser as the hydrothermal synthesis time increased, and the N 2 permeation amount was promptly reduced to a practicable level.
- the zeolite membrane of Comparative Example 1 did not become dense enough even when the hydrothermal synthesis time increased, because the different phase was synthesized as by-product in the zeolite membrane as described above.
- Example 2 to 8 and Comparative Examples 2 to 4 the N 2 permeation amount of the zeolite membrane was confirmed in the same way as Example 1 and Comparative Example 1. Similar to Example 1, the zeolite membrane 12 of each of Examples 2 to 8 became denser as the hydrothermal synthesis time increased, and the N 2 permeation amount was promptly reduced to a practicable level. On the other hand, similar to Comparative Example 1, the zeolite membrane of each of Comparative Examples 2 to 4 did not become dense enough even when the hydrothermal synthesis time increased.
- FIG. 9 is a SEM image of the surface of the AFX-type zeolite membrane 12 of Example 1.
- FIG. 10 is a SEM image of the surface of the AFX-type zeolite membrane of Comparative Example 1. In the zeolite membrane of Comparative Example 1 shown in FIG. 10 , surface abnormality occurs in the surface of the zeolite membrane at positions surrounded by circles with a reference sign 84 .
- the surface abnormality includes, for example, different phase crystal resulting from alkali metal and/or alkaline earth metal, amorphia, pinhole, or the like.
- surface abnormality can hardly be observed in the surface of the zeolite membrane 12 .
- FIGS. 11 and 12 are SEM images of the surfaces of the DDR-type zeolite membranes 12 of Examples 6 and 7.
- FIG. 13 is a SEM image of the surface of the DDR-type zeolite membrane of Comparative Example 3.
- surface abnormality of the zeolite membrane 12 i.e., whitish granular portions in the drawing
- FIG. 12 surface abnormality of the zeolite membrane 12 can hardly be observed.
- surface abnormality i.e., areas where whitish granular portions are continuous or fused in the drawing
- the percentage of surface abnormality (hereinafter, referred to as “surface abnormality percentage”) in the surface of the zeolite membrane 12 is preferably less than or equal to 15%.
- the surface abnormality percentage is a percentage of total area of surface abnormality existing in the surface of the zeolite membrane 12 in the total area of the surface of the zeolite membrane 12 .
- the surface abnormality percentage in the zeolite membrane 12 is more preferably less than or equal to 10%, and yet more preferably less than or equal to 1%.
- the lower limit of the surface abnormality percentage is not particularly limited.
- the surface abnormality percentage is typically greater than or equal to 0.01%, and more typically greater than or equal to 0.1%.
- the aforementioned surface abnormality percentage is obtained as below.
- a region having a predetermined size is specified in the SEM image of the surface of the zeolite membrane 12 , and the surface abnormality percentage in the region is calculated by dividing the total area of surface abnormality existing in the region by the total area of the region.
- an average of surface abnormality percentages calculated in ten regions in the SEM image is obtained as the surface abnormality percentage of the surface of the zeolite membrane 12 .
- the surface abnormality percentages of the zeolite membranes 12 of Examples 1 to 5, and 7 were less than or equal to 1%, and the surface abnormality percentage of the zeolite membrane 12 of Example 6 was 6%.
- the surface abnormality percentage of the zeolite membrane of Example 8 was 6%.
- the surface abnormality percentage of the zeolite membrane of Comparative Example 1 was greater than 15%, and the surface abnormality percentage of the zeolite membrane of Comparative Example 2 was greater than 20%.
- the surface abnormality percentage of the zeolite membrane of Comparative Example 3 was greater than 80%.
- the support 11 is a porous ceramic support for supporting a zeolite membrane.
- the hydraulic conductivity of the support 11 is less than or equal to 1.1 ⁇ 10 ⁇ 3 m/s.
- the total content of alkali metal and alkaline earth metal in the surface part 116 within 30 ⁇ m from the surface 114 in the depth direction perpendicular to the surface 114 is less than or equal to 1% by weight.
- the total content of alkali metal and alkaline earth metal in the surface part 116 is reduced to less than or equal to 1% by weight, and this suppresses elution of alkali metal and alkaline earth metal from the surface part 116 during hydrothermal synthesis for production of the zeolite membrane 12 .
- the hydraulic conductivity of the support 11 is reduced to less than or equal to 1.1 ⁇ 10 ⁇ 3 m/s. Therefore, even when alkali metal and alkaline earth metal are eluted in the surface part 116 , eluted alkali metal and alkaline earth metal can be suppressed from flowing out of the surface 114 of the support 11 into the starting material solution and the zeolite membrane 12 during synthesis. As a result, it is possible to suppress occurrence of abnormality in the zeolite membrane 12 due to alkali metal and/or alkaline earth metal.
- the abnormality which is suppressed from occurring by the support 11 includes followings: synthesis of a zeolite membrane having a composition ratio different from a desired composition ratio, performance degradation of the zeolite membrane due to different phase synthesized as by-product in the zeolite membrane, defect (e.g., pinholes) caused by inhibition of synthesis of the zeolite membrane, or the like.
- the total content of alkali metal and alkaline earth metal in the support layer 113 may be greater than 1% by weight.
- the porosity of the surface part 116 in the support 11 is preferably less than or equal to 50%. Because the porosity is reduced in this manner, elution of alkali metal and alkaline earth metal from the surface part 116 during hydrothermal synthesis can be further suppressed. Even when alkali metal and alkaline earth metal are eluted in the surface part 116 , eluted alkali metal and alkaline earth metal can be further suppressed from flowing out of the surface 114 of the support 11 into the starting material solution and the zeolite membrane 12 during synthesis. As a result, it is possible to further suppress occurrence of abnormality in the zeolite membrane 12 .
- the support 11 preferably includes the intermediate layer 112 including the surface part 116 , and the support layer 113 having a mean particle diameter greater than that of the intermediate layer 112 .
- the support layer 113 supports the intermediate layer 112 from the side opposite to the surface 114 of the intermediate layer 112 which comes into contact with the zeolite membrane 12 .
- the zeolite membrane complex 1 includes the above support 11 , and the zeolite membrane 12 formed on the surface 114 of the support 11 . This makes it possible to provide the zeolite membrane complex 1 including the dense zeolite membrane 12 with little abnormality due to alkali metal and/or alkaline earth metal.
- the percentage of surface abnormality in the surface of the zeolite membrane 12 is preferably less than or equal to 15%. This makes it possible to provide the zeolite membrane complex 1 including the denser zeolite membrane 12 .
- the thickness of the zeolite membrane 12 is preferably greater than or equal to 0.1 ⁇ m and less than or equal to 30 ⁇ m. It is therefore possible to appropriately satisfy both of separation performance and permeance in the zeolite membrane 12 .
- the structure of the zeolite membrane complex 1 is particularly suitable to a zeolite membrane complex including the zeolite membrane 12 which has the silica/alumina ratio greater than or equal to 10 (i.e., the zeolite membrane 12 in which the content of SiO 2 is 10 times or more the content of Al 2 O 3 ) and thereby is relatively likely to be adversely affected by alkali metal and alkaline earth metal.
- the method of producing the zeolite membrane complex 1 includes the step (step S 11 ) of preparing the above support 11 , the step (step S 12 ) of preparing seed crystals, the step (step S 13 ) of depositing the seed crystals on the porous support 11 , and the step (step S 14 ) of immersing the support 11 in a starting material solution and growing zeolite from the seed crystals by hydrothermal synthesis, to thereby form the zeolite membrane 12 on the support 11 . It is therefore possible to easily produce the zeolite membrane complex 1 including the dense zeolite membrane 12 with little abnormality due to alkali metal and/or alkaline earth metal.
- the above separation method includes the step (step S 21 ) of preparing the zeolite membrane complex 1 , and the step (step S 22 ) of supplying a mixture of substances containing a plurality of types of gases or liquids to the zeolite membrane complex 1 and allowing a high-permeability substance in the mixture of substances to permeate through the zeolite membrane complex 1 , to thereby separate the high-permeability substance from other substances.
- the separation method can efficiently separate the mixture of substances.
- the separation method is particularly suitable to separation of the mixture of substances includes at least one of following substances: hydrogen, helium, nitrogen, oxygen, water, steam, carbon monoxide, carbon dioxide, nitrogen oxide, ammonia, sulfur oxide, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- the support 11 , the zeolite membrane complex 1 , the method of producing the zeolite membrane complex 1 , and the separation method described above may be modified in various ways.
- the porosity of the surface part 116 in the support 11 may be greater than 50%.
- the support 11 does not necessarily have to be a double-layer structure composed of the intermediate layer 112 and the support layer 113 , and the support 11 may be, for example, a multilayer structure in which three or more layers having different mean particle diameters or the like are laminated one above another.
- the support 11 may be a single-layer structure composed of a single layer. In this case, a portion of the single layer within 30 ⁇ m from a surface is the aforementioned surface part 116 .
- the percentage of surface abnormality in the surface of the zeolite membrane 12 may be greater than 15%.
- the thickness of the zeolite membrane 12 may be less than 0.1 ⁇ m or greater than 30 ⁇ m.
- the composition of the zeolite membrane 12 may be changed in various ways.
- the content of SiO 2 in the zeolite membrane 12 may be less than 10 times the content of Al 2 O 3 .
- the content of Al 2 O 3 in the zeolite membrane 12 may be substantially 0% by weight.
- the ceramic support according to the present invention can be used, for example, for supporting a zeolite membrane which is available as a gas separation membrane.
- the zeolite membrane complex according to the present invention can be used in various fields using zeolites as a gas separator membrane, a separator membrane for substances other than gases, an adsorbent membrane for various substances, or the like.
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Abstract
Description
- The present application is a continuation application of International Application No. PCT/JP2019/322, filed on Jan. 9, 2019, which claims priority to Japanese Patent Application No. 2018-67398, filed on Mar. 30, 2018. The contents of these applications are incorporated herein by reference in their entirety.
- The present invention relates to a ceramic support, a zeolite membrane complex, a method of producing a zeolite membrane complex, a separation method of mixture of substances using a zeolite membrane complex.
- Currently, various kinds of researches and developments are carried out on applications, such as separation of specific molecules, adsorption of molecules, using a molecular sieving function of zeolite in the form of a zeolite membrane complex which is obtained by forming a zeolite membrane on a support.
- A method of immersing a porous ceramic support formed of aluminum oxide or the like in a starting material solution and synthesizing a zeolite membrane on the support by hydrothermal synthesis is known as one of methods of producing zeolite membrane complexes. Since the hydrothermal synthesis is performed under high temperature and pressure, there is a possibility that constituent components in the support may be eluted into the starting material solution. The substances eluted from the support may have an adverse effect on synthesis of zeolite membrane. Specifically, a zeolite membrane having a composition ratio different from a desired composition ratio may be synthesized. Performance of zeolite membrane may be degraded because of different phase synthesized as by-product in the zeolite membrane. Alternatively, defective coating on the support surface (e.g., pinholes in the zeolite membrane or the like) may be caused since the formation of the zeolite membrane is inhibited.
- Thus, Japanese Patent No. 3316173 (Document 1) proposes a technique for reducing an elution amount of a support into a starting material solution by forming the support with tantalum oxide or niobium oxide.
- On the other hand, Japanese Patent No. 4961322 (Document 2) proposes an alumina substrate which is used as a support for zeolite membrane and which contains 1% to 4% by weight of alkali metal oxide and/or alkaline earth metal oxide.
- International Publication WO 2016/084845 (Document 3) discloses a zeolite membrane complex in which part of a zeolite membrane penetrates into an inside of a porous support. When producing the zeolite membrane complex, inorganic particles are deposited on the support by direct rubbing or the like, and then the zeolite membrane is formed. As above, by depositing the inorganic particles on the support to form a layer of the inorganic particles in pores of the support, the zeolite membrane is suppressed from excessively penetrating into the pores of the support.
- The support of
Document 1 is formed of expensive material that is tantalum oxide or niobium oxide, and thus, production cost of the zeolite membrane complex increases. Since the support ofDocument 2 contains a relatively large amount of alkali metal or alkaline earth metal, there may be a case where abnormality (for example, difference in a composition ratio of the zeolite membrane, performance degradation due to different phase synthesized as by-product, or defect such as pinholes) occurs in the zeolite membrane by elution of alkali metal or alkaline earth metal from the support during hydrothermal synthesis. Also in the support of Document 3, since the surface of the support having the inorganic particles is partially exposed outside of the inorganic particles and is in contact with the starting material solution, alkali metal or alkaline earth metal contained in the support as a sintering additive or impurities is eluted from the support during hydrothermal synthesis. Thus, in a similar way to the support ofDocument 2, there may be a case where abnormality occurs in the zeolite membrane because of eluted alkali metal or alkaline earth metal. - The present invention is intended for a porous ceramic support for supporting a zeolite membrane. In the ceramic support according to a preferable embodiment of the present invention, a hydraulic conductivity is less than or equal to 1.1×10−3 m/s, and a total content of alkali metal and alkaline earth metal in a surface part within 30 μm from a surface in a depth direction perpendicular to the surface is less than or equal to 1% by weight. By the present invention, it is possible to suppress occurrence of abnormality in the zeolite membrane.
- Preferably, a porosity of the surface part is less than or equal to 50%.
- Preferably, the support includes an intermediate layer including the surface part, and a support layer that supports the intermediate layer from a side opposite to a surface of the intermediate layer which comes into contact with a zeolite membrane, the support layer having a mean particle diameter greater than that of the intermediate layer.
- The present invention is also intended for a zeolite membrane complex. The zeolite membrane complex according to a preferable embodiment of the present invention includes the above ceramic support, and a zeolite membrane formed on the ceramic support.
- Preferably, a percentage of surface abnormality in a surface of the zeolite membrane is less than or equal to 15%.
- Preferably, a thickness of the zeolite membrane is greater than or equal to 0.1 μm and less than or equal to 30 μm.
- Preferably, a content of silicon oxide in the zeolite membrane is 10 times or more a content of aluminum oxide.
- The present invention is also intended for a method of producing a zeolite membrane complex. The method of producing a zeolite membrane complex according to a preferable embodiment of the present invention includes a) preparing the above ceramic support, b) preparing seed crystals, c) depositing the seed crystals on the ceramic support, and d) immersing the ceramic support in a starting material solution and growing zeolite from the seed crystals by hydrothermal synthesis, to thereby form a zeolite membrane on the ceramic support.
- The present invention is also intended for a separation method. The separation method according to a preferable embodiment of the present invention includes a) preparing the above zeolite membrane complex, and b) supplying a mixture of substances containing a plurality of types of gases or liquids to the zeolite membrane complex and allowing a high-permeability substance in the mixture of substances to permeate through the zeolite membrane complex, to thereby separate the high-permeability substance from other substances.
- Preferably, the mixture of substances includes at least one of following substances: hydrogen, helium, nitrogen, oxygen, water, steam, carbon monoxide, carbon dioxide, nitrogen oxide, ammonia, sulfur oxide, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
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FIG. 1 is a sectional view of a zeolite membrane complex; -
FIG. 2 is an enlarged sectional view of the zeolite membrane complex; -
FIG. 3 is a flowchart of production of the zeolite membrane complex; -
FIG. 4 is a view of a separation apparatus; -
FIG. 5 is a flowchart of separation of a mixture of substances; -
FIG. 6 is an X-ray diffraction pattern of a zeolite membrane according to an example; -
FIG. 7 is an X-ray diffraction pattern of a zeolite membrane according to a comparative example; -
FIG. 8 is a view showing a relationship between hydrothermal synthesis time and nitrogen permeation amount; -
FIG. 9 is a view of a surface of the zeolite membrane according to the example; -
FIG. 10 is a view of a surface of the zeolite membrane according to the comparative example; -
FIG. 11 is a view of a surface of a zeolite membrane according to an example; -
FIG. 12 is a view of a surface of a zeolite membrane according to an example; and -
FIG. 13 is a view of a surface of a zeolite membrane according to a comparative example. -
FIG. 1 is a sectional view of azeolite membrane complex 1 according to an embodiment of the present invention. Thezeolite membrane complex 1 includes a porousceramic support 11 and azeolite membrane 12 formed on a surface of theceramic support 11. Theceramic support 11 is a support for supporting a zeolite membrane, and hereinafter is simply referred to as “support 11”. - In the example illustrated in
FIG. 1 , thesupport 11 is a monolith support, having a substantially circular columnar shape, where a plurality of throughholes 111 each extending in a longitudinal direction (i.e., the vertical direction in the drawing) are formed. Each through hole 111 (i.e., cell) has, for example, a substantially circular cross-section perpendicular to the longitudinal direction. In the illustration ofFIG. 1 , the diameter of the throughholes 111 is greater than the actual diameter, and the number of throughholes 111 is smaller than the actual number. Thezeolite membrane 12 is formed on the inner surfaces of the throughholes 111 and covers substantially the entire inner surfaces of the throughholes 111. InFIG. 1 , thezeolite membrane 12 is illustrated with bold lines. - The
support 11 has a length (i.e., the length in the vertical direction in the drawing) of, for example, 10 cm to 200 cm. Thesupport 11 has an outer diameter of, for example, 0.5 cm to 30 cm. The distance between the central axes of each pair of adjacent throughholes 111 is, for example, in the range of 0.3 mm to 10 mm. The surface roughness (Ra) of thesupport 11 is, for example, in the range of 0.1 μm to 2.0 μm and preferably in the range of 0.2 μm to 1.0 μm. Alternatively, thesupport 11 may have a different shape such as a honeycomb shape, a flat plate shape, a tubular shape, a circular cylindrical shape, a circular columnar shape, or a polygonal prism shape. When having a tubular shape, thesupport 11 has a thickness of, for example, 0.1 mm to 10 mm. - In the present embodiment, the
support 11 is a porous member permeable to gases and liquids (i.e., fluids). Thezeolite membrane 12 is a molecular separation membrane that separates a specific substance from a mixed fluid obtained by mixing a plurality of types of substances, using a molecular sieving function. For example, thezeolite membrane 12 may be used as a gas separation membrane that separates a specific gas from a mixed gas containing a plurality of types of gases. Alternatively, thezeolite membrane 12 may be used as a liquid separation membrane that separates a specific liquid from a mixed liquid containing a plurality of types of liquids. Thezeolite membrane 12 may be used as a separation membrane that separates a specific substance from a mixed fluid obtained by mixing a gas(es) and a liquid(s). Thezeolite membrane 12 may be used as a pervaporation membrane. Thezeolite membrane complex 1 may be used for other applications. - As the material for the
support 11, various ceramics may be employed as long as they have chemical stability in the step of forming thezeolite membrane 12 on the surface. Examples of the ceramic sintered compact to be selected as the material for thesupport 11 include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. In the present embodiment, thesupport 11 contains at least one of alumina, silica, and mullite. Thesupport 11 may contain an inorganic binder. The inorganic binder may be at least one of titania, mullite, easily sinterable alumina, silica, glass frit, clay minerals, and easily sinterable cordierite. Thesupport 11 contains alkali metal and/or alkaline earth metal. The alkali metal and alkaline earth metal are, for example, sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), or the like. - The
support 11 has a hydraulic conductivity less than or equal to 1.1×10−3 m/s, preferably less than or equal to 5.8×10−4 m/s, and more preferably less than or equal to 2.3×10−4 m/s. The lower limit of the hydraulic conductivity of thesupport 11 is not particularly limited as long as it is greater than 0 m/s. The hydraulic conductivity is typically greater than or equal to 1.1×10−5 m/s, and more typically greater than or equal to 1.2×10−4 m/s. - The hydraulic conductivity of the
support 11 was measured as below. First, by sealing one end of thesupport 11 in the longitudinal direction, one side of each through hole 111 (i.e., cell) of thesupport 11 was blocked. Subsequently, distilled water was supplied into the throughholes 111 from the other end of thesupport 11 in the longitudinal direction. At this time, the flow rate, pressure, and temperature of the supplied distilled water were measured. Next, the flow rate of distilled water that is led out from the outer side face of thesupport 11 through thesupport 11 was measured. The measured results were converted into values under a pressurized condition of 0.1 MPa at a water temperature of 25° C., and the hydraulic conductivity that is an amount of water per unit area which permeates through thesupport 11 per unit time was obtained on the basis of the converted values. -
FIG. 2 is a sectional view of part of thezeolite membrane complex 1 in enlarged dimensions. Thesupport 11 is a layered structure including anintermediate layer 112 and asupport layer 113. The material for each of theintermediate layer 112 and thesupport layer 113 may be any of the above-described materials. Theintermediate layer 112 and thesupport layer 113 may be formed of the same material, or may be formed of different materials. Theintermediate layer 112 is in direct contact with thezeolite membrane 12 to support thezeolite membrane 12. Thesurface 114 of theintermediate layer 112 which is in contact with thezeolite membrane 12 is the inner surfaces of the throughholes 111 of thesupport 11. Thesupport layer 113 supports theintermediate layer 112 from a side opposite to thezeolite membrane 12. In other words, thesupport layer 113 supports theintermediate layer 112 from the side opposite to thesurface 114 of theintermediate layer 112 which is in contact with thezeolite membrane 12. InFIG. 2 , a portion of thesupport 11 in the vicinity of theintermediate layer 112 is illustrated. - The
intermediate layer 112 is formed of particles having a relatively small mean particle diameter. Thesupport layer 113 is formed of particles having a mean particle diameter greater than that of theintermediate layer 112. The mean particle diameter of the particles constituting the intermediate layer 112 (i.e., framework particles) is preferably in the range of 0.001 μm to 100 μm, more preferably in the range of 0.01 μm to 80 μm, and yet more preferably in the range of 0.1 μm to 50 μm. The mean particle diameter of the particles constituting the support layer 113 (i.e., framework particles) is preferably in the range of 5 μm to 200 μm, more preferably in the range of 25 μm to 170 μm, and yet more preferably in the range of 50 μm to 150 μm. A polished surface formed by polishing theintermediate layer 112 is observed with a scanning electron microscope (SEM), and an average of particle diameters of twenty framework particles which are randomly selected is obtained as the mean particle diameter of theintermediate layer 112. The particle diameter of each framework particle is obtained as an average of the maximum diameter and the minimum diameter of the framework particle. The same applies to the mean particle diameter of thesupport layer 113. - The mean pore diameter of the
intermediate layer 112 is less than the mean pore diameter of thesupport layer 113. The mean pore diameter of theintermediate layer 112 is preferably in the range of 0.001 μm to 1 μm, more preferably in the range of 0.01 μm to 1 μm, and yet more preferably in the range of 0.05 μm to 0.5 μm. The mean pore diameter of thesupport layer 113 is preferably in the range of 0.5 μm to 50 μm, more preferably in the range of 1 μm to 30 μm, and yet more preferably in the range of 10 μm to 25 μm. The mean pore diameters of theintermediate layer 112 and thesupport layer 113 can be measured by, for example, a mercury porosimeter, a perm porosimeter, or a nano-perm porosimeter. - The porosity of the
intermediate layer 112 is preferably less than or equal to 50%, more preferably less than or equal to 40%, and yet more preferably less than or equal to 30%. The lower limit of the porosity of theintermediate layer 112 is not particularly limited as long as it is greater than 0%. The porosity is typically greater than or equal to 5%, and more typically greater than or equal to 10%. The porosity of thesupport layer 113 is preferably in the range of 5% to 50%, more preferably in the range of 10% to 45%, and yet more preferably in the range of 15% to 40%. The porosity of thesupport layer 113 was measured by mercury injection with only thesupport layer 113 as the measurement target. The porosity of theintermediate layer 112 was obtained by acquiring an image of the section of theintermediate layer 112 with an electron microscope and by performing an image analysis on an image obtained by binarizing the acquired image. - The thickness of the
intermediate layer 112 is, for example, in the range of 5 μm to 500 μm, preferably in the range of 10 μm to 400 μm, and more preferably in the range of 15 μm to 300 μm. The thickness of theintermediate layer 112 is a distance between thesurface 114 of theintermediate layer 112 and thesurface 115 of thesupport layer 113 in a depth direction substantially perpendicular to thesurface 114 of the intermediate layer 112 (i.e., the radial direction of the throughhole 111 of the support 11). The positions of thesurface 114 of theintermediate layer 112 and thesurface 115 of thesupport layer 113 can be obtained, for example, by observing the SEM image of the section of thesupport 11. - In the following description, a portion of the
support 11 within 30 μm from thesurface 114 in the above depth direction is referred to as a “surface part 116”. In other words, thesurface part 116 refers to, in thesupport 11, the whole of the portion between a position at 30 μm depth from thesurface 114 and thesurface 114 of thesupport 11. When the thickness of theintermediate layer 112 is greater than 30 μm, the whole of thesurface part 116 is included in theintermediate layer 112 and part of theintermediate layer 112 exists between thesurface part 116 and thesupport layer 113, as shown inFIG. 2 . When the thickness of theintermediate layer 112 is 30 μm, thesurface part 116 is identical to theintermediate layer 112. In any of these cases, theintermediate layer 112 includes the whole of thesurface part 116. - The porosity of the
surface part 116 is the same as that of theintermediate layer 112. Specifically, the porosity of thesurface part 116 is preferably less than or equal to 50%, more preferably less than or equal to 40%, and yet more preferably less than or equal to 30%. The lower limit of the porosity of thesurface part 116 is not particularly limited as long as it is greater than 0%. The porosity is typically greater than or equal to 5%, and more typically greater than or equal to 10%. The mean particle diameter of the framework particles and the mean pore diameter in thesurface part 116 are the same as those of theintermediate layer 112. - As described above, although the
support 11 contains at least one of alkali metal and alkaline earth metal, thesupport 11 may not contain both of them as appropriate. In this regard, when thesupport 11 does not contain both of alkali metal and alkaline earth metal, the sintering temperature of thesupport 11 tends to increase. The total content of alkali metal and alkaline earth metal in thesurface part 116 is less than or equal to 1% by weight, preferably less than or equal to 0.5% by weight, more preferably less than or equal to 0.1% by weight. The lower limit of the total content is not particularly limited. The total content is typically greater than or equal to 0.0001% by weight, and more typically greater than or equal to 0.001% by weight. The total content of alkali metal and alkaline earth metal can be measured by X-ray photoelectron spectrometry. - The
intermediate layer 112 is produced, for example, as below. First, an aggregate for theintermediate layer 112, an organic binder, a pH adjuster, and a surfactant are added to water, and they are mixed for 12 hours or more with a ball mill. - The purpose of mixing is not pulverization of the intermediate layer aggregate but peptization (loosening), and thus, balls having a lower hardness than the intermediate layer aggregate are used in the ball mill. For example, when the intermediate layer aggregate is made of alumina, zirconia balls are used in the ball mill. The slurry concentration (i.e., concentration of the intermediate layer aggregate) in ball milling is preferably less than or equal to 50%. Since the slurry concentration is made less than or equal to 50%, it is conceivable that the organic binder, the pH adjuster, and the surfactant become easy to act on the intermediate layer aggregate. After that, the above slurry is diluted with a predetermined amount of water. A defoamer is preferably added to the water. Further, it is preferable that a pH adjuster is added to the water to substantially equalize the pH of the water containing the defoamer and the pH adjuster with the pH of the slurry before dilution with the water. Therefore, occurrence of re-flocculation due to change in pH of the slurry by the defoamer can be suppressed. Next, the slurry diluted with the water is degassed with stirring under vacuum, and therefore the slurry for the
intermediate layer 112 is prepared. Since the dispersibility of the slurry for theintermediate layer 112 is improved by the above step, it is possible to obtain theintermediate layer 112 having high strength with reduced total content of alkali metal and alkaline earth metal even when the firing temperature is relatively low. An inorganic binder (e.g., titanium oxide or the like) may be added as a sintering additive to the slurry for theintermediate layer 112 if necessary. - The thickness of the
zeolite membrane 12 is, for example, in the range of 0.1 μm to 30 μm, preferably in the range of 0.5 μm to 20 μm, and more preferably in the range of 1 μm to 10 μm. As the thickness of thezeolite membrane 12 increases, separation performance improves. As the thickness of thezeolite membrane 12 decreases, permeance increases. The surface roughness (Ra) of thezeolite membrane 12 is, for example, 5 μm or less, preferably 2 μm or less. - The type of the zeolite constituting the
zeolite membrane 12 is not particularly limited. When thezeolite membrane 12 is used as a separation membrane, the maximum number of membered rings in the zeolite is preferably 6 or 8 from the view point of permeation amount of permeable substances and separation performance. More preferably, the maximum number of membered rings in thezeolite membrane 12 is 8. - The
zeolite membrane 12 is made of, for example, AFX-type zeolite. In other words, thezeolite membrane 12 is made of a zeolite having a framework type code “AFX” assigned by the International Zeolite Association. In this case, the intrinsic pore diameter of the zeolite constituting thezeolite membrane 12 is 0.34 nm×0.36 nm. The intrinsic pore diameter of thezeolite membrane 12 is smaller than the mean pore diameter of thesupport 11. - The
zeolite membrane 12 is not limited to the AFX-type zeolite, but may also be zeolite having any one of other structures. Thezeolite membrane 12 may be any type of zeolite, for example, AEI-type, AEN-type, AFN-type, AFV-type, CHA-type, DDR-type, ERI-type, ETL-type, GIS-type, LEV-type, LTA-type, RHO-type, and SAT-type. - The
zeolite membrane 12 contains, for example, one or more of the followings: silicon (Si), aluminum (Al), and phosphorus (P). In the present embodiment, thezeolite membrane 12 is made of aluminosilicate zeolite containing at least Al, Si, and O (oxygen). In the present embodiment, thezeolite membrane 12 contains aluminum oxide (Al2O3) and silicon dioxide (SiO2). - In the
zeolite membrane 12, the content of SiO2 is preferably 10 times or more the content of Al2O3. In other words, the silica/alumina ratio in thezeolite membrane 12 is preferably greater than or equal to 10. The silica/alumina ratio is more preferably greater than or equal to 12, and yet more preferably greater than or equal to 20. The upper limit of the silica/alumina ratio in thezeolite membrane 12 is not particularly limited. The silica/alumina ratio is typically less than or equal to 10000, and more typically less than or equal to 1000. - Next, an example of the procedure for producing the
zeolite membrane complex 1 will be described with reference toFIG. 3 . First, asupport 11 for use in the production of thezeolite membrane complex 1 is prepared (step S11). Additionally, seed crystals for use in the production of thezeolite membrane 12 are prepared (step S12). For example, AFX-type zeolite powder is synthesized by hydrothermal synthesis, and the seed crystals are acquired from the zeolite powder. This zeolite powder may be used as-is as seed crystals, or may be processed into seed crystals by, for example, pulverization. Step S11 and step S12 may be performed in parallel, or step S12 may be performed before step S11. - Then, the
porous support 11 is immersed in a solution in which the seed crystals are dispersed, so that the seed crystals are deposited on the support 11 (step S13). Alternatively, a solution in which the seed crystals are dispersed may be brought into contact with a portion of thesupport 11 on which thezeolite membrane 12 is desired to be formed, so that the seed crystals are deposited on thesupport 11. In this way, a seed-crystal-deposited support is prepared. The seed crystals may be deposited by other methods on thesupport 11. - The
support 11 with the seed crystals deposited thereon is immersed in a starting material solution. The starting material solution is prepared by, for example, dissolving substances such as an Si source, Al source, and a structure-directing agent (hereinafter, also referred to as an “SDA”) in a solvent such as water. The starting material solution has, for example, a composition of 1Al2O3:23SiO2:10Na2O:2.8SDA:1000H2O. As the SDA contained in the starting material solution, for example, 1,4-diazabicyclo[2.2.2]octane-C4-diquat dibromide can be used in the case of AFX-type zeolite. - Then, AFX-type zeolite is grown by hydrothermal synthesis using the seed crystals as nuclei to form an AFX-
type zeolite membrane 12 on the support 11 (step S14). The temperature of the hydrothermal synthesis is preferably in the range of 110 to 200° C. and, for example, 160° C. The hydrothermal synthesis time is preferably in the range of 10 to 100 hours and, for example, 30 hours. The composition of the AFX-type zeolite membrane 12 can be adjusted by adjusting, for example, the composition ratio of the Si source and the Al source in the starting material solution. - After the hydrothermal synthesis is completed, the
support 11 and thezeolite membrane 12 are rinsed with deionized water. After the rinsing, thesupport 11 and thezeolite membrane 12 are dried at, for example, 80° C. After thesupport 11 and thezeolite membrane 12 have been dried, thezeolite membrane 12 is subjected to heat treatment so as to burn and remove the SDA in thezeolite membrane 12 and to cause micropores in thezeolite membrane 12 to come through the membrane (step S15). The heating temperature and heating time for thezeolite membrane 12 are, for example, 450° C. and 50 hours. In this way, the aforementionedzeolite membrane complex 1 is obtained. In the case where any SDA is not used for production of thezeolite membrane 12, step S15 of burning and removing the SDA is omitted. - Next, the separation of a mixture of substances using the
zeolite membrane complex 1 will be described with reference toFIGS. 4 and 5 .FIG. 4 is a view of aseparation apparatus 2.FIG. 5 is flowchart of the separation of the mixture of substances by theseparation apparatus 2. - The
separation apparatus 2 supplies a mixture of substances containing a plurality of types of fluids (i.e., gases or liquids) to thezeolite membrane complex 1 and allows a substance with high permeability in the mixture of substances to pass through thezeolite membrane complex 1 so as to separate the substance from other substances. The separation by theseparation apparatus 2 may be performed for the purpose of, for example, extracting a substance with high permeability from the mixture of substances or for the purpose of condensing a substance with low permeability. - As described above, the mixture of substances (i.e., a mixture of fluids) may be a mixed gas containing a plurality of types of gases, or may be a mixed liquid containing a plurality of types of liquids, or may be a gas-liquid two-phase fluid containing both gas and liquid.
- In the
separation apparatus 2, the CO2 permeation amount (permeance) through thezeolite membrane complex 1 at a temperature of 20° C. to 400° C. is, for example, 100 nmol/m2·s·Pa or more. The ratio of CO2 permeation amount to CH4 leakage amount (permeance ratio) in thezeolite membrane complex 1 at a temperature of 20° C. to 400° C. is, for example, 100 or higher. These permeance and permeance ratio are values for the case where a difference in partial pressure of CO2 between the supply and permeation sides of thezeolite membrane complex 1 is 1.5 MPa. - The mixture of substances contains, for example, one or more types of substances including hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), water (H2O), steam (H2O), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxide, ammonia (NH3), sulfur oxide, hydrogen sulfide (H2S), sulfur fluoride, mercury (Hg), arsine (AsH3), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde.
- Nitrogen oxide is a compound of nitrogen and oxygen. The aforementioned nitrogen oxide is, for example, a gas called NOx such as nitrogen monoxide (NO), nitrogen dioxide (NO2), nitrous oxide (also referred to as dinitrogen monoxide) (N2O), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), or dinitrogen pentoxide (N2O5).
- Sulfur oxide is a compound of sulfur and oxygen. The aforementioned sulfur oxide is, for example, a gas called SOx such as sulfur dioxide (SO2) or sulfur trioxide (SO3).
- Sulfur fluoride is a compound of fluorine and sulfur. The aforementioned sulfur fluoride is, for example, disulfur difluoride (F—S—S—F, S═SF2), sulfur difluoride (SF2), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6), or disulfur decafluoride (S2F10).
- C1 to C8 hydrocarbons are hydrocarbons containing one to eight carbon atoms. C3 to C8 hydrocarbons may be any one of a linear-chain compound, a side-chain compound, and a cyclic compound. C3 to C8 hydrocarbons may also be either a saturated hydrocarbon (i.e., the absence of double bond and triple bond in a molecule) or an unsaturated hydrocarbon (i.e., the presence of double bond and/or triple bond in a molecule). C1 to C4 hydrocarbons are, for example, methane (CH4), ethane (C2H6), ethylene (C2H4), propane (C3H8), propylene (C3H6), normal butane (CH3(CH2)2CH3), isobutane (CH(CH3)3), 1-butene (CH2═CHCH2CH3), 2-butene (CH3CH═CHCH3), or isobutene (CH2═C(CH3)2).
- The aforementioned organic acid is, for example, carboxylic acid or sulfonic acid. The carboxylic acid is, for example, formic acid (CH2O2), acetic acid (C2H4O2), oxalic acid (C2H2O4), acrylic acid (C3H4O2), or benzoic acid (C6H5COOH). The sulfonic acid is, for example, ethane sulfonic acid (C2H6O3S). The organic acid may be a chain compound or a cyclic compound.
- The aforementioned alcohol is, for example, methanol (CH3OH), ethanol (C2H5OH), isopropanol (2-propanol) (CH3CH(OH)CH3), ethylene glycol (CH2(OH)CH2(OH)), or butanol (C4H9OH).
- The mercaptans are organic compounds with hydrogenated sulfur (SH) at their terminals and are substances called also thiol or thioalcohol. The aforementioned mercaptans are, for example, methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), or 1-propane thiol (C3H7SH).
- The aforementioned ester is, for example, formic acid ester or acetic acid ester.
- The aforementioned ether is, for example, dimethyl ether ((CH3)2O), methyl ethyl ether (C2H5OCH3), or diethyl ether ((C2H5)2O).
- The aforementioned ketone is, for example, acetone ((CH3)2CO), methyl ethyl ketone (C2H5COCH3), or diethyl ketone ((C2H5)2CO).
- The aforementioned aldehyde is, for example, acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO), or butanal (butyraldehyde) (C3H7CHO).
- The following description takes the example of the case where the mixture of substances separated by the
separation apparatus 2 is a mixed gas containing a plurality of types of gases. - The
separation apparatus 2 includes thezeolite membrane complex 1, sealingparts 21, anouter casing 22,seal members 23, asupply part 26, a first collectingpart 27, and a second collectingpart 28. Thezeolite membrane complex 1, the sealingparts 21, and theseal members 23 are housed in theouter casing 22. Thesupply part 26, the first collectingpart 27, and the second collectingpart 28 are disposed outside theouter casing 22 and connected to theouter casing 22. - The sealing
parts 21 are members mounted on the opposite ends of thesupport 11 of thezeolite membrane complex 1 in the longitudinal direction and for covering and sealing the opposite end faces of thesupport 11 in the longitudinal direction. The sealingparts 21 prevent the inflow and outflow of gases through the opposite end faces of thesupport 11. The sealingparts 21 are, for example, plate-like members formed of glass. The material and shape of each sealingpart 21 may be appropriately changed. The opposite ends of each throughhole 111 of thesupport 11 in the longitudinal direction are not covered by the sealingparts 21. This allows the inflow and outflow of the mixed gas from these opposite ends into the throughholes 111. - The
outer casing 22 is a tubular member of a substantially circular cylindrical shape. The longitudinal direction of the zeolite membrane complex 1 (the horizontal direction in the drawing) is substantially parallel to the longitudinal direction of theouter casing 22. One end of theouter casing 22 in the longitudinal direction (i.e., left-side end in the drawing) has asupply port 221, and the other end thereof has afirst exhaust port 222. The side face of theouter casing 22 has asecond exhaust port 223. The internal space of theouter casing 22 is an enclosed space isolated from the space around theouter casing 22. - The
supply port 221 is connected to thesupply part 26. Thesupply part 26 supplies a mixed gas to the internal space of theouter casing 22 through thesupply port 221. For example, thesupply part 26 is a blower that transmits the mixed gas under pressure toward theouter casing 22. The blower includes a pressure regulator that regulates the pressure of the mixed gas supplied to theouter casing 22. Thefirst exhaust port 222 is connected to the first collectingpart 27. Thesecond exhaust port 223 is connected to the second collectingpart 28. The first collectingpart 27 and the second collectingpart 28 are, for example, reservoirs for storing gases derived from theouter casing 22. - The
seal members 23 are disposed around the entire circumference between the outer side face of the zeolite membrane complex 1 (i.e., the outer side face of the support 11) and the inner side face of theouter casing 22 in the vicinity of the opposite ends of thezeolite membrane complex 1 in the longitudinal direction. Eachseal member 23 is a substantially circular ring-shaped member formed of a material impermeable to gases. For example, theseal members 23 are 0 rings formed of a resin having flexibility. Theseal members 23 are in intimate contact with the outer side face of thezeolite membrane complex 1 and the inner side face of theouter casing 22 around the entire circumference. The space between theseal member 23 and the outer side face of thezeolite membrane complex 1 and the space between theseal member 23 and the inner side face of theouter casing 22 are sealed so as to disable the passage of gases. - In the separation of the mixed gas, the
aforementioned separation apparatus 2 is provided to prepare the zeolite membrane complex 1 (step S21). Then, the mixed gas containing a plurality of types of gases having different permeability to thezeolite membrane 12 is supplied from thesupply part 26 to the internal space of theouter casing 22. For example, the mixed gas is composed primarily of CH4, CO2, and N2. The mixed gas may contain gases other than CH4, CO2, and N2. The pressure of the mixed gas supplied from thesupply part 26 to the internal space of the outer casing 22 (i.e., initial pressure) is in the range of, for example, 0.1 MPa to 10 MPa. - The mixed gas supplied from the
supply part 26 to theouter casing 22 is introduced from the left end of thezeolite membrane complex 1 in the drawing into each throughhole 111 of thesupport 11 as indicated by anarrow 251. Gases having high permeability (e.g., CO2 and N2; hereinafter referred to as “high-permeability substances”) in the mixed gas pass through thezeolite membrane 12 provided on the inner side face of each throughhole 111 and thesupport 11, and are emitted from the outer side face of thesupport 11. In this way, high-permeability substances are separated from gases with low permeability (e.g., CH4; hereinafter referred to as a “low-permeability substance”) in the mixed gas (step S22). The gases emitted from the outer side face of the support 11 (i.e., high-permeability substances) are collected by the second collectingpart 28 through thesecond exhaust port 223 as indicated by anarrow 253. - In the mixed gas, gases other than the gases that have passed through the
zeolite membrane 12 and the support 11 (hereinafter, referred to as “impermeable substances”) pass through each throughhole 111 of thesupport 11 from the left side to the right side in the drawing and are collected by the first collectingpart 27 through thefirst exhaust port 222 as indicated by anarrow 252. In addition to the aforementioned low-permeability substances, the impermeable substances may contain high-permeability substances that did not pass through thezeolite membrane 12. - Next, Examples 1 to 8 and Comparative Examples 1 to 4 each showing the relationship between properties of the
support 11 and separation performance of thezeolite membrane 12 will be described with reference to Tables 1 and 2, andFIGS. 6 to 13 . The hydraulic conductivity in Table 1 is a hydraulic conductivity of thesupport 11. The total content in Table 1 is a total content of alkali metal and alkaline earth metal in thesurface part 116. The porosity in Table 1 is a porosity of thesurface part 116. - In each of Examples 1 to 8, the hydraulic conductivity of the
support 11 was less than or equal to 1.1×10−3 m/s, and the total content of alkali metal and alkaline earth metal in thesurface part 116 was less than or equal to 1% by weight. On the other hand, in each of Comparative Examples 1 to 4, the hydraulic conductivity of the support was greater than 1.1×10−3 m/s, and the total content of alkali metal and alkaline earth metal in the surface part was greater than 1% by weight. -
TABLE 1 Hydraulic Type of Conductivity Total Content Porosity Zeolite (m/s) (%) (%) Membrane Example1 1.1 × 10−3 0.9 40 AFX Example2 5.8 × 10−4 0.9 37 AFX Example3 2.3 × 10−4 0.9 35 AFX Example4 2.1 × 10−4 0.5 35 AFX Example5 1.8 × 10−4 0.01 32 AFX Example6 5.8 × 10−4 0.9 37 DDR Example7 2.3 × 10−4 0.9 35 DDR Example8 1.3 × 10−4 0.1 35 CHA Comparative 1.9 × 10−3 1.1 52 AFX Example1 Comparative 1.3 × 10−3 1.1 49 AFX Example2 Comparative 1.9 × 10−3 1.1 52 DDR Example3 Comparative 1.9 × 10−3 1.1 52 CHA Example4 -
TABLE 2 Surface Abnormality Different Phase Percentage (XRD) (SEM) Denseness Example1 Absent 1% or less ∘ Example2 Absent 1% or less ∘ Example3 Absent 1% or less ∘ Example4 Absent 1% or less ∘ Example5 Absent 1% or less ∘ Example6 — 6% ∘ Example7 Absent 1% or less ∘ Example8 Absent Below detection limit ∘ Comparative Present 15%< x Example1 Comparative Present 20%< x Example2 Comparative Present 80%< x Example3 Comparative Present Below detection limit x Example4 -
FIG. 6 is an X-ray diffraction pattern obtained by measuring thezeolite membrane 12 of Example 1 with an X-ray diffraction (XRD) apparatus.FIG. 7 is an X-ray diffraction pattern obtained by measuring the zeolite membrane of Comparative Example 1 with the X-ray diffraction apparatus. In each ofFIGS. 6 and 7 , the X-ray diffraction pattern of the zeolite membrane is indicated by the solid line, and the X-ray diffraction pattern of AFX-type zeolite crystal is indicated by the dashed line. For the measurement of the X-ray diffraction pattern, MiniFlex600 manufactured by Rigaku Corporation was used. - The X-ray used for the X-ray diffraction is a CuKα line. Further, an output of the X-ray is 600 W. The tube voltage was 40 kV, the tube current was 15 mA, the scanning speed was 5°/min, and the scanning step was 0.02°. As a detector, a scintillation counter was used. The divergence slit was 1.25°, the scattering slit was 1.25°, the receiving slit was 0.3 mm, the incident solar slit was 5.0°, and the light-receiving solar slit was 5.0°. A monochromator was not used, and a nickel foil having a thickness of 0.015 mm was used as a CuKβ line filter.
- From
FIGS. 6 and 7 , it can be seen that the AFX-type zeolite membrane of Comparative Example 1 includes different phase having a different composition from that of the AFX-type zeolite while thezeolite membrane 12 of Example 1 is almost single-phase AFX-type zeolite. In Comparative Example 1 shown inFIG. 7 , peaks (and halos) corresponding to the different phase appear at positions indicated byarrows - Also in Examples 2 to 8 and Comparative Examples 2 to 4, the presence or absence of different phase was determined by XRD in the same way as Example 1 and Comparative Example 1. The
zeolite membrane 12 of each of Examples 2 to 5 was almost single-phase AFX-type zeolite and included almost no different phase, similar to Example 1. Meanwhile, the AFX-type zeolite membrane of Comparative Example 2 included different phase having a different composition from that of the AFX-type zeolite, similar to Comparative Example 1. Thezeolite membrane 12 of each of Examples 6 and 7 was almost single-phase DDR-type zeolite and included almost no different phase. Meanwhile, the DDR-type zeolite membrane of Comparative Example 3 included different phase having a different composition from that of the DDR-type zeolite. Thezeolite membrane 12 of Example 8 was almost single-phase CHA-type zeolite and included almost no different phase. Meanwhile, the CHA-type zeolite membrane of Comparative Example 4 included different phase having a different composition from that of the CHA-type zeolite. -
FIG. 8 is a view showing a relationship between hydrothermal synthesis time in production of thezeolite membrane 12 of Example 1 and N2 permeation amount (nmol/m2·s·Pa) in thezeolite membrane 12 synthesized by the hydrothermal synthesis. InFIG. 8 , the relationship in the zeolite membrane of Comparative Example 1 is also shown. Thezeolite membrane 12 of Example 1 became denser as the hydrothermal synthesis time increased, and the N2 permeation amount was promptly reduced to a practicable level. On the other hand, the zeolite membrane of Comparative Example 1 did not become dense enough even when the hydrothermal synthesis time increased, because the different phase was synthesized as by-product in the zeolite membrane as described above. - Also in Examples 2 to 8 and Comparative Examples 2 to 4, the N2 permeation amount of the zeolite membrane was confirmed in the same way as Example 1 and Comparative Example 1. Similar to Example 1, the
zeolite membrane 12 of each of Examples 2 to 8 became denser as the hydrothermal synthesis time increased, and the N2 permeation amount was promptly reduced to a practicable level. On the other hand, similar to Comparative Example 1, the zeolite membrane of each of Comparative Examples 2 to 4 did not become dense enough even when the hydrothermal synthesis time increased. - The aforementioned different phase grows together with growth of the zeolite membrane. Some of the different phase appear in the surface of the zeolite membrane, and others remain inside the zeolite membrane and do not appear in the surface.
FIG. 9 is a SEM image of the surface of the AFX-type zeolite membrane 12 of Example 1.FIG. 10 is a SEM image of the surface of the AFX-type zeolite membrane of Comparative Example 1. In the zeolite membrane of Comparative Example 1 shown inFIG. 10 , surface abnormality occurs in the surface of the zeolite membrane at positions surrounded by circles with areference sign 84. The surface abnormality includes, for example, different phase crystal resulting from alkali metal and/or alkaline earth metal, amorphia, pinhole, or the like. On the other hand, in thezeolite membrane 12 of Example 1 shown inFIG. 9 , surface abnormality can hardly be observed in the surface of thezeolite membrane 12. -
FIGS. 11 and 12 are SEM images of the surfaces of the DDR-type zeolite membranes 12 of Examples 6 and 7.FIG. 13 is a SEM image of the surface of the DDR-type zeolite membrane of Comparative Example 3. In thezeolite membrane 12 of Example 6 shown inFIG. 11 , surface abnormality of the zeolite membrane 12 (i.e., whitish granular portions in the drawing) slightly appears. In thezeolite membrane 12 of Example 7 shown inFIG. 12 , surface abnormality of thezeolite membrane 12 can hardly be observed. On the other hand, in the zeolite membrane of Comparative Example 3 shown inFIG. 13 , surface abnormality (i.e., areas where whitish granular portions are continuous or fused in the drawing) occurs at a lot of positions in the surface of thezeolite membrane 12. - In the
zeolite membrane complex 1 according to the present invention, the percentage of surface abnormality (hereinafter, referred to as “surface abnormality percentage”) in the surface of thezeolite membrane 12 is preferably less than or equal to 15%. The surface abnormality percentage is a percentage of total area of surface abnormality existing in the surface of thezeolite membrane 12 in the total area of the surface of thezeolite membrane 12. The surface abnormality percentage in thezeolite membrane 12 is more preferably less than or equal to 10%, and yet more preferably less than or equal to 1%. The lower limit of the surface abnormality percentage is not particularly limited. The surface abnormality percentage is typically greater than or equal to 0.01%, and more typically greater than or equal to 0.1%. - The aforementioned surface abnormality percentage is obtained as below. First, a region having a predetermined size is specified in the SEM image of the surface of the
zeolite membrane 12, and the surface abnormality percentage in the region is calculated by dividing the total area of surface abnormality existing in the region by the total area of the region. Then, an average of surface abnormality percentages calculated in ten regions in the SEM image is obtained as the surface abnormality percentage of the surface of thezeolite membrane 12. - The surface abnormality percentages of the
zeolite membranes 12 of Examples 1 to 5, and 7 were less than or equal to 1%, and the surface abnormality percentage of thezeolite membrane 12 of Example 6 was 6%. In the CHA-type zeolite membrane 12 of Example 8, surface abnormality such as different phase crystal was not observed in the SEM image of the surface of thezeolite membrane 12, and thus, “below detection limit” is put in Table 2. On the other hand, the surface abnormality percentage of the zeolite membrane of Comparative Example 1 was greater than 15%, and the surface abnormality percentage of the zeolite membrane of Comparative Example 2 was greater than 20%. The surface abnormality percentage of the zeolite membrane of Comparative Example 3 was greater than 80%. In the zeolite membrane of Comparative Example 4, surface abnormality was not observed in the SEM image, similar to Example 8. However, it is conceivable that, in Comparative Example 4, different phase which remains inside the zeolite membrane and which does not appear in the surface is more likely to exit, considering that the zeolite membrane has a low denseness as above. - As described above, the
support 11 is a porous ceramic support for supporting a zeolite membrane. The hydraulic conductivity of thesupport 11 is less than or equal to 1.1×10−3 m/s. In thesupport 11, the total content of alkali metal and alkaline earth metal in thesurface part 116 within 30 μm from thesurface 114 in the depth direction perpendicular to thesurface 114 is less than or equal to 1% by weight. - As above, the total content of alkali metal and alkaline earth metal in the
surface part 116 is reduced to less than or equal to 1% by weight, and this suppresses elution of alkali metal and alkaline earth metal from thesurface part 116 during hydrothermal synthesis for production of thezeolite membrane 12. The hydraulic conductivity of thesupport 11 is reduced to less than or equal to 1.1×10−3 m/s. Therefore, even when alkali metal and alkaline earth metal are eluted in thesurface part 116, eluted alkali metal and alkaline earth metal can be suppressed from flowing out of thesurface 114 of thesupport 11 into the starting material solution and thezeolite membrane 12 during synthesis. As a result, it is possible to suppress occurrence of abnormality in thezeolite membrane 12 due to alkali metal and/or alkaline earth metal. - As described above, the abnormality which is suppressed from occurring by the
support 11 includes followings: synthesis of a zeolite membrane having a composition ratio different from a desired composition ratio, performance degradation of the zeolite membrane due to different phase synthesized as by-product in the zeolite membrane, defect (e.g., pinholes) caused by inhibition of synthesis of the zeolite membrane, or the like. - Even if elution of alkali metal and alkaline earth metal occurs in a portion located deeper than the
surface part 116 in the support 11 (e.g., the support layer 113), it is conceivable that the synthesis of thezeolite membrane 12 is not adversely affected because the alkali metal and alkaline earth metal hardly reach thesurface 114 of thesupport 11. Thus, the total content of alkali metal and alkaline earth metal in thesupport layer 113 may be greater than 1% by weight. - As above, the porosity of the
surface part 116 in thesupport 11 is preferably less than or equal to 50%. Because the porosity is reduced in this manner, elution of alkali metal and alkaline earth metal from thesurface part 116 during hydrothermal synthesis can be further suppressed. Even when alkali metal and alkaline earth metal are eluted in thesurface part 116, eluted alkali metal and alkaline earth metal can be further suppressed from flowing out of thesurface 114 of thesupport 11 into the starting material solution and thezeolite membrane 12 during synthesis. As a result, it is possible to further suppress occurrence of abnormality in thezeolite membrane 12. - As above, the
support 11 preferably includes theintermediate layer 112 including thesurface part 116, and thesupport layer 113 having a mean particle diameter greater than that of theintermediate layer 112. Thesupport layer 113 supports theintermediate layer 112 from the side opposite to thesurface 114 of theintermediate layer 112 which comes into contact with thezeolite membrane 12. Thus, when selecting materials of thesupport layer 113 or the like, there is no necessity to consider the total content of alkali metal and alkaline earth metal in thesurface part 116, and the porosity of thesurface part 116. It is therefore possible to increase the degree of freedom in material selection of thesupport layer 113 and to facilitate production of thesupport 11. - The
zeolite membrane complex 1 includes theabove support 11, and thezeolite membrane 12 formed on thesurface 114 of thesupport 11. This makes it possible to provide thezeolite membrane complex 1 including thedense zeolite membrane 12 with little abnormality due to alkali metal and/or alkaline earth metal. - As above, the percentage of surface abnormality in the surface of the
zeolite membrane 12 is preferably less than or equal to 15%. This makes it possible to provide thezeolite membrane complex 1 including thedenser zeolite membrane 12. - In the
zeolite membrane complex 1, the thickness of thezeolite membrane 12 is preferably greater than or equal to 0.1 μm and less than or equal to 30 μm. It is therefore possible to appropriately satisfy both of separation performance and permeance in thezeolite membrane 12. - As above, occurrence of abnormality in the
zeolite membrane 12 due to alkali metal and/or alkaline earth metal can be suppressed in thezeolite membrane complex 1. Thus, the structure of thezeolite membrane complex 1 is particularly suitable to a zeolite membrane complex including thezeolite membrane 12 which has the silica/alumina ratio greater than or equal to 10 (i.e., thezeolite membrane 12 in which the content of SiO2 is 10 times or more the content of Al2O3) and thereby is relatively likely to be adversely affected by alkali metal and alkaline earth metal. - As above, the method of producing the
zeolite membrane complex 1 includes the step (step S11) of preparing theabove support 11, the step (step S12) of preparing seed crystals, the step (step S13) of depositing the seed crystals on theporous support 11, and the step (step S14) of immersing thesupport 11 in a starting material solution and growing zeolite from the seed crystals by hydrothermal synthesis, to thereby form thezeolite membrane 12 on thesupport 11. It is therefore possible to easily produce thezeolite membrane complex 1 including thedense zeolite membrane 12 with little abnormality due to alkali metal and/or alkaline earth metal. - The above separation method includes the step (step S21) of preparing the
zeolite membrane complex 1, and the step (step S22) of supplying a mixture of substances containing a plurality of types of gases or liquids to thezeolite membrane complex 1 and allowing a high-permeability substance in the mixture of substances to permeate through thezeolite membrane complex 1, to thereby separate the high-permeability substance from other substances. - As above, because the
zeolite membrane complex 1 includes thedense zeolite membrane 12 with little abnormality due to alkali metal and/or alkaline earth metal, the separation method can efficiently separate the mixture of substances. The separation method is particularly suitable to separation of the mixture of substances includes at least one of following substances: hydrogen, helium, nitrogen, oxygen, water, steam, carbon monoxide, carbon dioxide, nitrogen oxide, ammonia, sulfur oxide, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acid, alcohol, mercaptans, ester, ether, ketone, and aldehyde. - The
support 11, thezeolite membrane complex 1, the method of producing thezeolite membrane complex 1, and the separation method described above may be modified in various ways. - For example, the porosity of the
surface part 116 in thesupport 11 may be greater than 50%. - The
support 11 does not necessarily have to be a double-layer structure composed of theintermediate layer 112 and thesupport layer 113, and thesupport 11 may be, for example, a multilayer structure in which three or more layers having different mean particle diameters or the like are laminated one above another. Alternatively, thesupport 11 may be a single-layer structure composed of a single layer. In this case, a portion of the single layer within 30 μm from a surface is theaforementioned surface part 116. - In the
zeolite membrane complex 1, the percentage of surface abnormality in the surface of thezeolite membrane 12 may be greater than 15%. - In the
zeolite membrane complex 1, the thickness of thezeolite membrane 12 may be less than 0.1 μm or greater than 30 μm. - In the
zeolite membrane complex 1, the composition of thezeolite membrane 12 may be changed in various ways. For example, the content of SiO2 in thezeolite membrane 12 may be less than 10 times the content of Al2O3. The content of Al2O3 in thezeolite membrane 12 may be substantially 0% by weight. - In the
separation apparatus 2 and the separation method, substances other than the substance exemplified in the above description may be separated from the mixture of substances. - The configurations of the above-described preferred embodiments and variations may be appropriately combined as long as there are no mutual inconsistencies.
- While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations can be devised without departing from the scope of the invention.
- The ceramic support according to the present invention can be used, for example, for supporting a zeolite membrane which is available as a gas separation membrane. The zeolite membrane complex according to the present invention can be used in various fields using zeolites as a gas separator membrane, a separator membrane for substances other than gases, an adsorbent membrane for various substances, or the like.
-
-
- 1 Zeolite membrane complex
- 11 Support
- 12 Zeolite membrane
- 112 Intermediate layer
- 113 Support layer
- 114 Surface (of support)
- 116 Surface part
- S11 to S15, S21, S22 Step
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11135553B2 (en) * | 2016-03-31 | 2021-10-05 | Ngk Insulators, Ltd. | Porous support, method for manufacturing porous support, separation membrane structure, and method for manufacturing separation membrane structure |
US11298663B2 (en) * | 2018-08-28 | 2022-04-12 | Molecule Works Inc. | Thin metal/ceramic hybrid membrane sheet and filter |
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Family Cites Families (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2084005A (en) * | 1934-10-25 | 1937-06-15 | Richards Lorenzo Adolph | Auto irrigation system |
US2801186A (en) * | 1954-09-14 | 1957-07-30 | Du Pont | Composition and process |
US3395035A (en) * | 1963-10-01 | 1968-07-30 | Martin Marietta Corp | Resin impregnated ceramic heat shield and method of making |
US3346509A (en) * | 1964-06-12 | 1967-10-10 | Gulf Research Development Co | Co-precipitated silica-alumina catalyst process and composition |
US3506561A (en) * | 1964-11-16 | 1970-04-14 | Mobil Oil Corp | Method for making electrodes |
US3377265A (en) * | 1964-11-16 | 1968-04-09 | Mobil Oil Corp | Electrochemical electrode |
US3562183A (en) * | 1967-07-25 | 1971-02-09 | Aziende Colori Nazionali Aflin | Method of obtaining vanadium-containing catalysts for the vapor-phase oxidation of aromatic hydrocarbons |
US3468815A (en) * | 1967-09-11 | 1969-09-23 | Texaco Inc | Extended zeolitic structures |
US3672988A (en) * | 1969-02-25 | 1972-06-27 | Fuji Photo Film Co Ltd | Method of manufacturing bases for electrostatic recording material or electrophotographic material |
US3745127A (en) * | 1972-03-20 | 1973-07-10 | Us Army | Composition of matter containing carbon |
US3790475A (en) * | 1972-03-27 | 1974-02-05 | Corning Glass Works | Porous glass support material |
JP3316173B2 (en) | 1997-11-06 | 2002-08-19 | 株式会社ノリタケカンパニーリミテド | Substrate for supporting zeolite membrane |
GB9905560D0 (en) * | 1999-03-11 | 1999-05-05 | Exxon Chemical Patents Inc | Process for the manufacture of supported materials |
JP5148044B2 (en) * | 2004-03-17 | 2013-02-20 | 三菱化学株式会社 | Porous substrate |
BRPI0508601A (en) * | 2004-03-17 | 2007-07-31 | Bussan Nanotech Res Inst Inc | separation membrane |
US20070210493A1 (en) * | 2004-07-13 | 2007-09-13 | Ngk Insulators, Ltd. | Method for Producing Ceramic Porous Article |
JP5324067B2 (en) | 2006-08-22 | 2013-10-23 | 日本碍子株式会社 | Method for producing zeolite membrane |
JP4961322B2 (en) | 2007-10-19 | 2012-06-27 | 株式会社ニッカトー | Alumina substrate for zeolite membrane and method for producing the same |
JP4864061B2 (en) | 2008-10-08 | 2012-01-25 | 日本碍子株式会社 | Honeycomb structure and manufacturing method thereof |
US9216390B2 (en) * | 2010-07-15 | 2015-12-22 | Ohio State Innovation Foundation | Systems, compositions, and methods for fluid purification |
JP5360015B2 (en) * | 2010-08-18 | 2013-12-04 | 三菱化学株式会社 | Filter material |
JP2012110849A (en) * | 2010-11-25 | 2012-06-14 | Sumitomo Chemical Co Ltd | Honeycomb filter |
CN104220151B (en) * | 2012-03-30 | 2017-04-05 | 日本碍子株式会社 | Honeycomb shape ceramic porous article, its manufacture method, and honeycomb shape ceramic separation film structure |
US9399575B2 (en) * | 2012-04-05 | 2016-07-26 | The Regents Of The University Of Colorado, A Body Corporate | Methods and apparatus for gas-phase reduction/oxidation processes |
US20140357476A1 (en) * | 2013-05-30 | 2014-12-04 | Corning Incorporated | Formed ceramic substrate composition for catalyst integration |
ES2554648B1 (en) * | 2014-06-20 | 2016-09-08 | Consejo Superior De Investigaciones Científicas (Csic) | ITQ-55 material, preparation and use procedure |
CN106659987B (en) * | 2014-08-13 | 2020-02-28 | 旭化成株式会社 | Forward osmosis membrane and forward osmosis treatment system |
CN107078357B (en) * | 2014-11-13 | 2020-03-06 | 日本碍子株式会社 | Secondary battery using hydroxide ion-conductive ceramic separator |
EP3225297B1 (en) | 2014-11-25 | 2023-06-28 | Mitsubishi Chemical Corporation | Use of a porous support-cha zeolite membrane composite for separation of a gas mixture |
CN107427783A (en) * | 2015-03-31 | 2017-12-01 | 日本碍子株式会社 | Zeolite membrane structures body |
JP6670825B2 (en) | 2015-03-31 | 2020-03-25 | 日本碍子株式会社 | Zeolite membrane structure and method for producing the same |
CN108883377B (en) | 2016-03-31 | 2021-05-07 | 日本碍子株式会社 | Porous support, method for producing porous support, separation membrane structure, and method for producing separation membrane structure |
-
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11135553B2 (en) * | 2016-03-31 | 2021-10-05 | Ngk Insulators, Ltd. | Porous support, method for manufacturing porous support, separation membrane structure, and method for manufacturing separation membrane structure |
US11298663B2 (en) * | 2018-08-28 | 2022-04-12 | Molecule Works Inc. | Thin metal/ceramic hybrid membrane sheet and filter |
US11607650B2 (en) | 2018-08-28 | 2023-03-21 | Molecule Works Inc. | Thin metal/ceramic hybrid membrane sheet and filter |
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